[PATCH v7 00/10] Enable CMRR in fixed-RR VRR path

[PATCH v7 00/10] Enable CMRR in fixed-RR VRR path

[Mitul Golani]

The existing CMRR fractional-timing code was permanently
disabled (if (!HAS_CMRR || true)), eDP-only, and relied
on a heuristic to guess when the fractional path was needed.
This series reworks it into a generic, debugfs-driven feature,
which later will be controlled via userspace when respective
uapi will be in-palce.

Mitul Golani (10):
  drm/i915/vrr: Return from PSR2 compute config in case of CMRR enabled
  drm/i915/vrr: Restrict CMRR enable condition to VRR-TG-default
    platforms
  drm/i915/vrr: Add per-CRTC vrr/cmrr debugfs control
  drm/i915/vrr: Update AS_SDP target_rr_divider based on CMRR config
    request
  drm/i915/display: Move CMRR crtc_state members under VRR
  drm/i915/vrr: Compute CMRR fractional timings generically
  drm/i915/vrr: Latch CMRR ratio via fastset on debugfs write
  drm/i915/vrr: Program CMRR enable/disable from transcoder timings
  drm/i915/vrr: Dump CMRR state in the crtc state dump
  drm/i915/vrr: Enable cmrr

 drivers/gpu/drm/i915/display/intel_cmtg.c     |   2 +-
 .../drm/i915/display/intel_crtc_state_dump.c  |   3 +
 drivers/gpu/drm/i915/display/intel_display.c  |  10 +-
 .../drm/i915/display/intel_display_debugfs.c  |   2 +
 .../drm/i915/display/intel_display_types.h    |  17 +-
 drivers/gpu/drm/i915/display/intel_dp.c       |   9 +-
 drivers/gpu/drm/i915/display/intel_psr.c      |   6 +
 drivers/gpu/drm/i915/display/intel_vrr.c      | 387 ++++++++++++++----
 drivers/gpu/drm/i915/display/intel_vrr.h      |   2 +
 9 files changed, 339 insertions(+), 99 deletions(-)

-- 
2.48.1

[PATCH v7 01/10] drm/i915/vrr: Return from PSR2 compute config in case of CMRR enabled

[Mitul Golani]

CMRR is mutually exclusive to PSR2, do not enable PSR2 when CMRR is
enabled.

--v2:
- Restrict selective update config check (Ankit)
- Commit message change

--v3:
- Commit changes

--v4:
- Add check to psr2_config_valid (Jouni)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 40e3d7095996..5ddcede6db27 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1491,6 +1491,12 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 	int crtc_vdisplay = crtc_state->hw.adjusted_mode.crtc_vdisplay;
 	int psr_max_h = 0, psr_max_v = 0, max_bpp = 0;
 
+	if (crtc_state->cmrr.enable) {
+		drm_dbg_kms(display->drm,
+			    "Selective update cannot be enabled when CMRR is enabled\n");
+		return false;
+	}
+
 	if (!connector->dp.psr_caps.su_support || display->params.enable_psr == 1)
 		return false;
 
-- 
2.48.1

[PATCH v7 02/10] drm/i915/vrr: Restrict CMRR enable condition to VRR-TG-default platforms

[Mitul Golani]

CMRR is currently advertised on all HAS_CMRR platforms, but it depends
on the VRR timing generator being the default timing generator, which
currently only applies to DISPLAY_VER >= 30.

Gate the CMRR enable condition and readout accordingly so CMRR is only
reported on supported platforms.

No functional change.

--v2:
- Create a separate function to check if CMRR possible

--v3:
- Simplify commit message (Chaitanya)
- Remove redundant outer parenthesis (Chaitanya)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 51e4f3309b8b..b0c9101e6ed3 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -187,15 +187,21 @@ int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state)
 	return intel_vrr_vmax_vtotal(crtc_state) - crtc_state->vrr.guardband;
 }
 
+static bool intel_vrr_cmrr_possible(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+
+	return HAS_CMRR(display) && intel_vrr_always_use_vrr_tg(display);
+}
+
 static bool
 is_cmrr_frac_required(struct intel_crtc_state *crtc_state)
 {
-	struct intel_display *display = to_intel_display(crtc_state);
 	int calculated_refresh_k, actual_refresh_k, pixel_clock_per_line;
 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
 
 	/* Avoid CMRR for now till we have VRR with fixed timings working */
-	if (!HAS_CMRR(display) || true)
+	if (!intel_vrr_cmrr_possible(crtc_state) || true)
 		return false;
 
 	actual_refresh_k =
@@ -1066,7 +1072,7 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
 	trans_vrr_ctl = intel_de_read(display,
 				      TRANS_VRR_CTL(display, cpu_transcoder));
 
-	if (HAS_CMRR(display))
+	if (intel_vrr_cmrr_possible(crtc_state))
 		crtc_state->cmrr.enable = (trans_vrr_ctl & VRR_CTL_CMRR_ENABLE);
 
 	if (crtc_state->cmrr.enable) {
-- 
2.48.1

[PATCH v7 03/10] drm/i915/vrr: Add per-CRTC vrr/cmrr debugfs control

[Mitul Golani]

Add a per-CRTC debugfs file 'intel_vrr_target_refresh_rate' that lets
the user force a CMRR target refresh rate and video-mode requirement.

The file uses a "numerator/denominator" format:
  - numerator:   requested refresh rate in milli-Hz
                 (refresh rate in Hz * 1000, e.g. 60000 for 60 Hz)
  - denominator: 1000 for a 1:1 ratio (no video timing) or
                 1001 for the 1000/1001 video timing

Reading the file reports the currently stored values; writing updates
them. The file is created only on platforms with VRR and CMRR support.

--v2:
- Drop the "vrr" debugfs subdirectory and expose a single flat,
  intel_-prefixed "intel_vrr_cmrr" file (Jani, Nikula)
- Rename struct intel_crtc.cmrr to force_cmrr to make its purpose
  explicit (Chaitanya)
- Fix parse comment: numerator unit is milli-Hz, not KHz (Chaitanya)
- Add debugfs/intel_ prefixes to the debugfs handler functions (Chaitanya)
- Expand commit message with debugfs entry semantics (Chaitanya)

--v3:
- Rename debugfs function and file name (Chaitanya)
- Remove railing new line at EOF (Chaitanya)
- Update CMRR guard conditions (Chaitanya)
- Add 0/0 default case. (Ramanaidu)

--v4:
- Correct CMRR guard check while creating debugfs

--v5:
- Commit message update (Chaitanya)
- Add support for 0/0 writing (Validation)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 .../drm/i915/display/intel_display_debugfs.c  |   2 +
 .../drm/i915/display/intel_display_types.h    |   5 +
 drivers/gpu/drm/i915/display/intel_vrr.c      | 112 ++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vrr.h      |   2 +
 4 files changed, 121 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index 3f02868ef105..2bbf4760dc30 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -49,6 +49,7 @@
 #include "intel_psr.h"
 #include "intel_psr_regs.h"
 #include "intel_vdsc.h"
+#include "intel_vrr.h"
 #include "intel_wm.h"
 #include "intel_tc.h"
 
@@ -1395,6 +1396,7 @@ void intel_crtc_debugfs_add(struct intel_crtc *crtc)
 	intel_drrs_crtc_debugfs_add(crtc);
 	intel_fbc_crtc_debugfs_add(crtc);
 	hsw_ips_crtc_debugfs_add(crtc);
+	intel_vrr_crtc_debugfs_add(crtc);
 
 	debugfs_create_file("i915_current_bpc", 0444, root, crtc,
 			    &i915_current_bpc_fops);
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index b7cc361fd955..46dd980b315a 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1553,6 +1553,11 @@ struct intel_crtc {
 		u64 flip_count;
 	} dc_balance;
 
+	struct {
+		u32 numerator;
+		u32 denominator;
+	} force_cmrr;
+
 	int scanline_offset;
 
 	struct {
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index b0c9101e6ed3..615c8fa8c063 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -4,6 +4,10 @@
  *
  */
 
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+
 #include <drm/drm_print.h>
 #include <drm/intel/step.h>
 
@@ -1237,3 +1241,111 @@ int intel_vrr_dcb_vmax_vblank_start_final(const struct intel_crtc_state *crtc_st
 
 	return intel_vrr_vblank_start(crtc_state, VRR_DCB_VMAX(tmp) + 1);
 }
+
+static
+int intel_vrr_cmrr_parse_ratio(char *str, u32 *numerator, u32 *denominator)
+{
+	char *sep;
+	int ret;
+
+	/*
+	 * Parse a "numerator/denominator" CMRR ratio string. The numerator
+	 * is the requested refresh rate in milli-Hz (refresh rate in Hz * 1000)
+	 * and the denominator selects the timing: 1000 for a 1:1 ratio
+	 * (no video timing) or 1001 for the 1000/1001 video timing.
+	 */
+
+	sep = strchr(str, '/');
+	if (!sep)
+		return -EINVAL;
+
+	*sep = '\0';
+
+	ret = kstrtou32(strim(str), 10, numerator);
+	if (ret)
+		return ret;
+
+	ret = kstrtou32(strim(sep + 1), 10, denominator);
+	if (ret)
+		return ret;
+	/*
+	 * "0/0" clears any previously configured CMRR override.
+	 * A zero numerator already means "CMRR not requested" in
+	 * intel_vrr_cmrr_compute_config(), so just let it through.
+	 */
+	if (*numerator == 0 && *denominator == 0)
+		return 0;
+
+	if (*numerator == 0)
+		return -EINVAL;
+
+	if (*denominator != 1000 && *denominator != 1001)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int intel_vrr_debugfs_target_rr_show(struct seq_file *m, void *data)
+{
+	struct intel_crtc *crtc = m->private;
+
+	seq_printf(m, "%u/%u\n", crtc->force_cmrr.numerator, crtc->force_cmrr.denominator);
+
+	return 0;
+}
+
+static int intel_vrr_debugfs_target_rr_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, intel_vrr_debugfs_target_rr_show, inode->i_private);
+}
+
+static ssize_t intel_vrr_debugfs_target_rr_write(struct file *file, const char __user *ubuf,
+						 size_t len, loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	struct intel_crtc *crtc = m->private;
+	u32 numerator, denominator;
+	char kbuf[32];
+	int ret;
+
+	if (len >= sizeof(kbuf))
+		return -EINVAL;
+
+	if (copy_from_user(kbuf, ubuf, len))
+		return -EFAULT;
+
+	kbuf[len] = '\0';
+
+	ret = intel_vrr_cmrr_parse_ratio(kbuf, &numerator, &denominator);
+	if (ret)
+		return ret;
+
+	if (crtc->force_cmrr.numerator == numerator &&
+	    crtc->force_cmrr.denominator == denominator)
+		return len;
+
+	crtc->force_cmrr.numerator = numerator;
+	crtc->force_cmrr.denominator = denominator;
+
+	return len;
+}
+
+static const struct file_operations intel_vrr_debugfs_target_rr_fops = {
+	.owner = THIS_MODULE,
+	.open = intel_vrr_debugfs_target_rr_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = intel_vrr_debugfs_target_rr_write,
+};
+
+void intel_vrr_crtc_debugfs_add(struct intel_crtc *crtc)
+{
+	struct intel_crtc_state *crtc_state = to_intel_crtc_state(crtc->base.state);
+
+	if (!intel_vrr_cmrr_possible(crtc_state))
+		return;
+
+	debugfs_create_file("intel_vrr_target_refresh_rate", 0600, crtc->base.debugfs_entry,
+			    crtc, &intel_vrr_debugfs_target_rr_fops);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
index 55e9c429f579..19c7990be1b2 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.h
+++ b/drivers/gpu/drm/i915/display/intel_vrr.h
@@ -56,4 +56,6 @@ int intel_vrr_dcb_vmax_vblank_start_next(const struct intel_crtc_state *crtc_sta
 int intel_vrr_dcb_vmin_vblank_start_final(const struct intel_crtc_state *crtc_state);
 int intel_vrr_dcb_vmax_vblank_start_final(const struct intel_crtc_state *crtc_state);
 
+void intel_vrr_crtc_debugfs_add(struct intel_crtc *crtc);
+
 #endif /* __INTEL_VRR_H__ */
-- 
2.48.1

[PATCH v7 04/10] drm/i915/vrr: Update AS_SDP target_rr_divider based on CMRR config request

[Mitul Golani]

Compute AS_SDP target_rr_divider based on actual CMRR request
requirement.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 113d767e62e9..9e2db310b7d8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3125,6 +3125,7 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
 	struct drm_dp_as_sdp *as_sdp = &crtc_state->infoframes.as_sdp;
 	const struct drm_display_mode *adjusted_mode =
 		&crtc_state->hw.adjusted_mode;
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 
 	/*
 	 * #FIXME: SDP/infoframe updates aren’t truly atomic, and with the new
@@ -3145,7 +3146,11 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
 	if (crtc_state->cmrr.enable) {
 		as_sdp->mode = DP_AS_SDP_FAVT_TRR_REACHED;
 		as_sdp->target_rr = drm_mode_vrefresh(adjusted_mode);
-		as_sdp->target_rr_divider = true;
+
+		if (crtc->force_cmrr.denominator == 1001)
+			as_sdp->target_rr_divider = true;
+		else
+			as_sdp->target_rr_divider = false;
 	} else if (crtc_state->vrr.enable) {
 		as_sdp->mode = DP_AS_SDP_AVT_DYNAMIC_VTOTAL;
 	} else {
-- 
2.48.1

[PATCH v7 05/10] drm/i915/display: Move CMRR crtc_state members under VRR

[Mitul Golani]

Move CMRR crtc state members under VRR infrastructure as
it is enabled during fixed-refresh-rate VRR timing generator
is enabled.

--v2:
- Move cmrr structure under vrr umbrella.
- Remove dups. (Jani)

--v3:
- Update commit message

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 drivers/gpu/drm/i915/display/intel_cmtg.c     |  2 +-
 drivers/gpu/drm/i915/display/intel_display.c  | 10 +++----
 .../drm/i915/display/intel_display_types.h    | 12 ++++----
 drivers/gpu/drm/i915/display/intel_dp.c       |  2 +-
 drivers/gpu/drm/i915/display/intel_psr.c      |  2 +-
 drivers/gpu/drm/i915/display/intel_vrr.c      | 30 +++++++++----------
 6 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.c b/drivers/gpu/drm/i915/display/intel_cmtg.c
index c8e0f90af910..3c0f5b2fb2e7 100644
--- a/drivers/gpu/drm/i915/display/intel_cmtg.c
+++ b/drivers/gpu/drm/i915/display/intel_cmtg.c
@@ -326,7 +326,7 @@ void intel_cmtg_set_vrr_ctl(const struct intel_crtc_state *crtc_state)
 		  XELPD_VRR_CTL_VRR_GUARDBAND(crtc_state->vrr.guardband);
 
 	/* TODO: The code below may need to be revisited once CMRR is enabled */
-	if (crtc_state->cmrr.enable)
+	if (crtc_state->vrr.cmrr.enable)
 		vrr_ctl |= VRR_CTL_CMRR_ENABLE;
 
 	intel_de_write(display, TRANS_VRR_CTL(display, cmtg_transcoder), vrr_ctl);
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 9dfd095f325f..8ce762188665 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -950,8 +950,8 @@ static bool vrr_params_changed(const struct intel_crtc_state *old_crtc_state,
 static bool cmrr_params_changed(const struct intel_crtc_state *old_crtc_state,
 				const struct intel_crtc_state *new_crtc_state)
 {
-	return old_crtc_state->cmrr.cmrr_m != new_crtc_state->cmrr.cmrr_m ||
-		old_crtc_state->cmrr.cmrr_n != new_crtc_state->cmrr.cmrr_n;
+	return old_crtc_state->vrr.cmrr.cmrr_m != new_crtc_state->vrr.cmrr.cmrr_m ||
+		old_crtc_state->vrr.cmrr.cmrr_n != new_crtc_state->vrr.cmrr.cmrr_n;
 }
 
 static bool intel_crtc_vrr_enabling(struct intel_atomic_state *state,
@@ -5536,9 +5536,9 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 		PIPE_CONF_CHECK_I(vrr.flipline);
 		PIPE_CONF_CHECK_I(vrr.vsync_start);
 		PIPE_CONF_CHECK_I(vrr.vsync_end);
-		PIPE_CONF_CHECK_LLI(cmrr.cmrr_m);
-		PIPE_CONF_CHECK_LLI(cmrr.cmrr_n);
-		PIPE_CONF_CHECK_BOOL(cmrr.enable);
+		PIPE_CONF_CHECK_LLI(vrr.cmrr.cmrr_m);
+		PIPE_CONF_CHECK_LLI(vrr.cmrr.cmrr_n);
+		PIPE_CONF_CHECK_BOOL(vrr.cmrr.enable);
 		PIPE_CONF_CHECK_I(vrr.dc_balance.vmin);
 		PIPE_CONF_CHECK_I(vrr.dc_balance.vmax);
 		PIPE_CONF_CHECK_I(vrr.dc_balance.guardband);
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 46dd980b315a..20a07ea06b5e 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1408,13 +1408,13 @@ struct intel_crtc_state {
 			u16 max_increase, max_decrease;
 			u16 vblank_target;
 		} dc_balance;
-	} vrr;
 
-	/* Content Match Refresh Rate state */
-	struct {
-		bool enable;
-		u64 cmrr_n, cmrr_m;
-	} cmrr;
+		/* Content Match Refresh Rate state */
+		struct {
+			bool enable;
+			u64 cmrr_n, cmrr_m;
+		} cmrr;
+	} vrr;
 
 	/* Stream Splitter for eDP MSO */
 	struct {
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9e2db310b7d8..7f13595f40c1 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3143,7 +3143,7 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
 	as_sdp->revision = 0x2;
 	as_sdp->vtotal = intel_vrr_vmin_vtotal(crtc_state);
 
-	if (crtc_state->cmrr.enable) {
+	if (crtc_state->vrr.cmrr.enable) {
 		as_sdp->mode = DP_AS_SDP_FAVT_TRR_REACHED;
 		as_sdp->target_rr = drm_mode_vrefresh(adjusted_mode);
 
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 5ddcede6db27..d2009e317024 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1491,7 +1491,7 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 	int crtc_vdisplay = crtc_state->hw.adjusted_mode.crtc_vdisplay;
 	int psr_max_h = 0, psr_max_v = 0, max_bpp = 0;
 
-	if (crtc_state->cmrr.enable) {
+	if (crtc_state->vrr.cmrr.enable) {
 		drm_dbg_kms(display->drm,
 			    "Selective update cannot be enabled when CMRR is enabled\n");
 		return false;
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 615c8fa8c063..6d3333fd5281 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -235,12 +235,12 @@ cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool video_mode_required)
 		multiplier_n = 1000;
 	}
 
-	crtc_state->cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
-					      multiplier_n);
+	crtc_state->vrr.cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
+						  multiplier_n);
 	vtotal = DIV_ROUND_UP_ULL(mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_n),
-				  crtc_state->cmrr.cmrr_n);
+				  crtc_state->vrr.cmrr.cmrr_n);
 	adjusted_pixel_rate = mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_m);
-	crtc_state->cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->cmrr.cmrr_n);
+	crtc_state->vrr.cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->vrr.cmrr.cmrr_n);
 
 	return vtotal;
 }
@@ -258,7 +258,7 @@ void intel_vrr_compute_cmrr_timings(struct intel_crtc_state *crtc_state)
 	crtc_state->vrr.vmin = crtc_state->vrr.vmax;
 	crtc_state->vrr.flipline = crtc_state->vrr.vmin;
 
-	crtc_state->cmrr.enable = true;
+	crtc_state->vrr.cmrr.enable = true;
 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
 }
 
@@ -651,15 +651,15 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
 		return;
 	}
 
-	if (crtc_state->cmrr.enable) {
+	if (crtc_state->vrr.cmrr.enable) {
 		intel_de_write(display, TRANS_CMRR_M_HI(display, cpu_transcoder),
-			       upper_32_bits(crtc_state->cmrr.cmrr_m));
+			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_m));
 		intel_de_write(display, TRANS_CMRR_M_LO(display, cpu_transcoder),
-			       lower_32_bits(crtc_state->cmrr.cmrr_m));
+			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_m));
 		intel_de_write(display, TRANS_CMRR_N_HI(display, cpu_transcoder),
-			       upper_32_bits(crtc_state->cmrr.cmrr_n));
+			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_n));
 		intel_de_write(display, TRANS_CMRR_N_LO(display, cpu_transcoder),
-			       lower_32_bits(crtc_state->cmrr.cmrr_n));
+			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_n));
 	}
 
 	intel_vrr_set_fixed_rr_timings(crtc_state, cpu_transcoder);
@@ -980,7 +980,7 @@ void intel_vrr_enable(const struct intel_crtc_state *crtc_state)
 	intel_vrr_enable_dc_balancing(crtc_state);
 
 	if (!intel_vrr_always_use_vrr_tg(display))
-		intel_vrr_tg_enable(crtc_state, crtc_state->cmrr.enable);
+		intel_vrr_tg_enable(crtc_state, crtc_state->vrr.cmrr.enable);
 }
 
 void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
@@ -1077,12 +1077,12 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
 				      TRANS_VRR_CTL(display, cpu_transcoder));
 
 	if (intel_vrr_cmrr_possible(crtc_state))
-		crtc_state->cmrr.enable = (trans_vrr_ctl & VRR_CTL_CMRR_ENABLE);
+		crtc_state->vrr.cmrr.enable = (trans_vrr_ctl & VRR_CTL_CMRR_ENABLE);
 
-	if (crtc_state->cmrr.enable) {
-		crtc_state->cmrr.cmrr_n =
+	if (crtc_state->vrr.cmrr.enable) {
+		crtc_state->vrr.cmrr.cmrr_n =
 			intel_de_read64_2x32(display, TRANS_CMRR_N_LO(display, cpu_transcoder));
-		crtc_state->cmrr.cmrr_m =
+		crtc_state->vrr.cmrr.cmrr_m =
 			intel_de_read64_2x32(display, TRANS_CMRR_M_LO(display, cpu_transcoder));
 	}
 
-- 
2.48.1

[PATCH v7 06/10] drm/i915/vrr: Compute CMRR fractional timings generically

[Mitul Golani]

Rework the fractional CMRR computation into a generic,
transcoder-agnostic helper driven by an explicit per-CRTC debugfs
target, replacing the previous disabled, eDP-only code path. Compute
CMRR_M and CMRR_N timings based on the video mode requirements. Note
that the CMRR enable path is wired up separately; this patch only lays
down the generic computation. Remove computation of mode_flags,
I915_MODE_FLAG_VRR, as CMRR is being moved to the fixed refresh rate
path. Also return early from the CMRR computation if the existing
computation is already sufficient.

--v2:
- Derive video_mode locally instead of caching it in the persistent
  struct intel_crtc state (Jani, Chaitanya)
- Fix numerator unit in comment: milli-Hz, not kHz (Chaitanya)
- Fix "requirement" typo and clarify that CMRR is not yet enabled in
  the commit message (Chaitanya)
- Fix precision issue while computing the M/N ratio (Chaitanya)
- Rename multiplier_m and multiplier_n to improve readability
  (Chaitanya)
- Compute vtotal as it is required for dithering as per the algorithm
  implementation (Chaitanya)
- Replace the misleading adjusted_pixel_rate with dividend, which is
  more descriptive

--v3:
- Mention the rationale for not computing I915_MODE_FLAG_VRR
  (Chaitanya)
- Remove the redundant return statement at the end of the CMRR
  computation (Chaitanya)
- Correct cmrr_n calculation (Chaitanya)
- Add an early return if the current computation is already sufficient
  to drive the mode without CMRR (Chaitanya)
- Round up requested_refresh_rate (Validation)
- Fix integer overflow

--v4:
- Update cmrr_n calculation to avoid aggressive dithering
- Use div64_u64 to truncate to the floor value instead of
  DIV_ROUND_UP_ULL, which rounds up to the ceiling value
- Add a TODO comment to the cmrr_n calculation
- Add a condition for custom refresh rate requests
- Update the CMRR computation comment block in compute_config

--v5:
- Simplify computation
- Correct typo in commit message (Chaitanya)
- Compute early return condition (Chaitanya)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 143 ++++++++++++-----------
 1 file changed, 78 insertions(+), 65 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 6d3333fd5281..7746b2ead7d1 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -27,9 +27,6 @@
 #include "skl_prefill.h"
 #include "skl_watermark.h"
 
-#define FIXED_POINT_PRECISION		100
-#define CMRR_PRECISION_TOLERANCE	10
-
 /*
  * Tunable parameters for DC Balance correction.
  * These are captured based on experimentations.
@@ -198,68 +195,86 @@ static bool intel_vrr_cmrr_possible(const struct intel_crtc_state *crtc_state)
 	return HAS_CMRR(display) && intel_vrr_always_use_vrr_tg(display);
 }
 
-static bool
-is_cmrr_frac_required(struct intel_crtc_state *crtc_state)
+static void
+intel_vrr_cmrr_compute_config(struct intel_crtc_state *crtc_state)
 {
-	int calculated_refresh_k, actual_refresh_k, pixel_clock_per_line;
+	struct intel_display *display = to_intel_display(crtc_state);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
+	u64 dividend;
+	u32 mode_rate_mhz;
+	u32 requested_rate_mhz = crtc->force_cmrr.numerator;
+	int rr_multiplier = 1, rr_divider = 1;
 
-	/* Avoid CMRR for now till we have VRR with fixed timings working */
-	if (!intel_vrr_cmrr_possible(crtc_state) || true)
-		return false;
-
-	actual_refresh_k =
-		drm_mode_vrefresh(adjusted_mode) * FIXED_POINT_PRECISION;
-	pixel_clock_per_line =
-		adjusted_mode->crtc_clock * 1000 / adjusted_mode->crtc_htotal;
-	calculated_refresh_k =
-		pixel_clock_per_line * FIXED_POINT_PRECISION / adjusted_mode->crtc_vtotal;
-
-	if ((actual_refresh_k - calculated_refresh_k) < CMRR_PRECISION_TOLERANCE)
-		return false;
-
-	return true;
-}
-
-static unsigned int
-cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool video_mode_required)
-{
-	int multiplier_m = 1, multiplier_n = 1, vtotal, desired_refresh_rate;
-	u64 adjusted_pixel_rate;
-	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
+	if (!intel_vrr_cmrr_possible(crtc_state))
+		return;
 
-	desired_refresh_rate = drm_mode_vrefresh(adjusted_mode);
+	/* No CMRR ratio configured through debugfs */
+	if (!requested_rate_mhz)
+		return;
 
-	if (video_mode_required) {
-		multiplier_m = 1001;
-		multiplier_n = 1000;
+	/* Requested rate must match the mode's nominal (integer) refresh rate */
+	if (DIV_ROUND_CLOSEST(requested_rate_mhz, 1000) !=
+			drm_mode_vrefresh(adjusted_mode)) {
+		drm_dbg_kms(display->drm,
+			    "[CRTC:%d:%s] CMRR requested %u.%03u Hz doesn't match mode %d Hz\n",
+			    crtc->base.base.id, crtc->base.name,
+			    requested_rate_mhz / 1000, requested_rate_mhz % 1000,
+			    drm_mode_vrefresh(adjusted_mode));
+		return;
 	}
 
-	crtc_state->vrr.cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
-						  multiplier_n);
-	vtotal = DIV_ROUND_UP_ULL(mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_n),
-				  crtc_state->vrr.cmrr.cmrr_n);
-	adjusted_pixel_rate = mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_m);
-	crtc_state->vrr.cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->vrr.cmrr.cmrr_n);
-
-	return vtotal;
-}
+	/* Actual rate produced by the current timings, in milli-Hz */
+	mode_rate_mhz =
+		DIV_ROUND_CLOSEST_ULL((u64)adjusted_mode->crtc_clock * 1000 * 1000,
+				      adjusted_mode->crtc_vtotal *
+				      adjusted_mode->crtc_htotal);
 
-static
-void intel_vrr_compute_cmrr_timings(struct intel_crtc_state *crtc_state)
-{
 	/*
-	 * TODO: Compute precise target refresh rate to determine
-	 * if video_mode_required should be true. Currently set to
-	 * false due to uncertainty about the precise target
-	 * refresh Rate.
+	 * A 1:1 ratio (denominator == 1000) means no video timing is required
+	 * Any other ratio (e.g. 1000/1001) requires the video timing.
 	 */
-	crtc_state->vrr.vmax = cmrr_get_vtotal(crtc_state, false);
-	crtc_state->vrr.vmin = crtc_state->vrr.vmax;
-	crtc_state->vrr.flipline = crtc_state->vrr.vmin;
+	if (crtc->force_cmrr.denominator == 1000) {
+		rr_multiplier = 1;
+		rr_divider = 1;
+
+		/* Mode already hits the exact rate -> CMRR not needed */
+		if (DIV_ROUND_CLOSEST(mode_rate_mhz, 10) ==
+		    DIV_ROUND_CLOSEST(requested_rate_mhz, 10)) {
+			drm_dbg_kms(display->drm,
+				    "[CRTC:%d:%s] %u.%03u Hz can be driven without CMRR\n",
+				    crtc->base.base.id, crtc->base.name,
+				    requested_rate_mhz / 1000, requested_rate_mhz % 1000);
+			return;
+		}
+	} else {
+		rr_multiplier = 1000;
+		rr_divider = 1001;
+	}
 
-	crtc_state->vrr.cmrr.enable = true;
-	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
+	/*
+	 * Let pixel_clock_hz = adjusted_mode->crtc_clock * 1000.
+	 *
+	 * cmrr_n = (requested_rate_mhz x htotal x rr_multiplier) / 1000
+	 * cmrr_m = (pixel_clock_hz x rr_divider) % cmrr_n
+	 *
+	 * where requested_rate_mhz is the requested refresh rate in milli-Hz
+	 * and rr_multiplier/rr_divider = 1000/1001 when the video timing
+	 * is required, else 1/1. The integer vtotal term is tracked in SW
+	 * (it is the programmed mode vtotal) while the fractional part
+	 * represented by cmrr_m/cmrr_n is tracked in HW.
+	 *
+	 * TODO: Using the actual desired rate for cmrr_n in video
+	 * mode produces more aggressive vtotal dithering than
+	 * expected; revisit once the Bspec algorithm is clarified.
+	 */
+	crtc_state->vrr.cmrr.cmrr_n =
+		div64_u64((u64)requested_rate_mhz *
+			  adjusted_mode->crtc_htotal * rr_multiplier, 1000);
+	dividend = (u64)adjusted_mode->crtc_clock * rr_divider * 1000;
+	adjusted_mode->crtc_vtotal = div64_u64_rem(dividend,
+						   crtc_state->vrr.cmrr.cmrr_n,
+						   &crtc_state->vrr.cmrr.cmrr_m);
 }
 
 static
@@ -435,8 +450,6 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
 	struct intel_display *display = to_intel_display(crtc_state);
 	struct intel_connector *connector =
 		to_intel_connector(conn_state->connector);
-	struct intel_dp *intel_dp = intel_attached_dp(connector);
-	bool is_edp = intel_dp_is_edp(intel_dp);
 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
 	int vmin, vmax;
 
@@ -470,12 +483,17 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
 		vmax = vmin;
 	}
 
-	if (crtc_state->uapi.vrr_enabled && vmin < vmax)
+	if (crtc_state->uapi.vrr_enabled && vmin < vmax) {
 		intel_vrr_compute_vrr_timings(crtc_state, vmin, vmax);
-	else if (is_cmrr_frac_required(crtc_state) && is_edp)
-		intel_vrr_compute_cmrr_timings(crtc_state);
-	else
+	} else {
+		/*
+		 * CMRR is a fixed average Vtotal mode and is only computed on
+		 * the fixed refresh rate path. It is generic across transcoders
+		 * and gated on platform support and a valid debugfs ratio.
+		 */
+		intel_vrr_cmrr_compute_config(crtc_state);
 		intel_vrr_compute_fixed_rr_timings(crtc_state);
+	}
 
 	if (HAS_AS_SDP(display)) {
 		crtc_state->vrr.vsync_start =
@@ -1142,11 +1160,6 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
 
 	intel_vrr_get_dc_balance_config(crtc_state);
 
-	/*
-	 * #TODO: For Both VRR and CMRR the flag I915_MODE_FLAG_VRR is set for mode_flags.
-	 * Since CMRR is currently disabled, set this flag for VRR for now.
-	 * Need to keep this in mind while re-enabling CMRR.
-	 */
 	if (crtc_state->vrr.enable)
 		crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
 
-- 
2.48.1

[PATCH v7 07/10] drm/i915/vrr: Latch CMRR ratio via fastset on debugfs write

[Mitul Golani]

Writing the per-CRTC "intel_vrr_target_refresh_rate" debugfs file only
updates crtc->force_cmrr, a side channel that is not tracked by the
atomic state. The requested ratio therefore does not reach the hardware
until some unrelated commit recomputes the pipe config.

Kick an internal atomic commit for the CRTC from the debugfs write and
mark the CRTC mode as changed so the pipe config is recomputed.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 63 ++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 7746b2ead7d1..056d513ab637 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -8,10 +8,12 @@
 #include <linux/seq_file.h>
 #include <linux/string.h>
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_print.h>
 #include <drm/intel/step.h>
 
 #include "intel_alpm.h"
+#include "intel_atomic.h"
 #include "intel_cmtg.h"
 #include "intel_crtc.h"
 #include "intel_de.h"
@@ -1312,6 +1314,58 @@ static int intel_vrr_debugfs_target_rr_open(struct inode *inode, struct file *fi
 	return single_open(file, intel_vrr_debugfs_target_rr_show, inode->i_private);
 }
 
+/*
+ * Force an internal fastset commit on @crtc so that a CMRR ratio programmed
+ * via debugfs gets recomputed and latched into hardware. CMRR only alters the
+ * (average) vtotal, which is handled by the LRR fastset path, so this does not
+ * trigger a full modeset (no blank out).
+ */
+static int intel_vrr_cmrr_fastset_force(struct intel_crtc *crtc)
+{
+	struct intel_display *display = to_intel_display(crtc);
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_atomic_commit *state;
+	struct intel_crtc_state *crtc_state;
+	int ret = 0;
+
+	state = drm_atomic_commit_alloc(display->drm);
+	if (!state)
+		return -ENOMEM;
+
+	drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE);
+
+	state->acquire_ctx = &ctx;
+	to_intel_atomic_state(state)->internal = true;
+
+retry:
+	crtc_state = intel_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto out;
+	}
+
+	if (!crtc_state->hw.active)
+		goto out;
+
+	/* Mark mode as changed to trigger a pipe recompute + update() */
+	crtc_state->uapi.mode_changed = true;
+
+	ret = drm_atomic_commit(state);
+out:
+	if (ret == -EDEADLK) {
+		drm_atomic_commit_clear(state);
+		ret = drm_modeset_backoff(&ctx);
+		if (!ret)
+			goto retry;
+	}
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+	drm_atomic_commit_put(state);
+
+	return ret;
+}
+
 static ssize_t intel_vrr_debugfs_target_rr_write(struct file *file, const char __user *ubuf,
 						 size_t len, loff_t *offp)
 {
@@ -1340,6 +1394,15 @@ static ssize_t intel_vrr_debugfs_target_rr_write(struct file *file, const char _
 	crtc->force_cmrr.numerator = numerator;
 	crtc->force_cmrr.denominator = denominator;
 
+	/*
+	 * The debugfs value is a side channel that is not tracked by the atomic
+	 * state, so kick an internal fastset commit to recompute and latch the
+	 * new CMRR parameters without a full modeset.
+	 */
+	ret = intel_vrr_cmrr_fastset_force(crtc);
+	if (ret)
+		return ret;
+
 	return len;
 }
 
-- 
2.48.1

[PATCH v7 08/10] drm/i915/vrr: Program CMRR enable/disable from transcoder timings

[Mitul Golani]

Split the CMRR M/N register programming into intel_vrr_enable_cmrr()
and intel_vrr_disable_cmrr(), and drive them from
intel_vrr_set_fixed_rr_timings() based on crtc_state->vrr.cmrr.enable.

VRR_CTL_CMRR_ENABLE is not set explicitly, writing TRANS_CMRR_N_HI
arms CMRR in hardware. Drop the now-unused cmrr_enable
argument to intel_vrr_tg_enable().

No functional change intended for non-CMRR configurations.

--v2:
- Commit message changes.
- Added Simplified enable/disable sequence. (Chaitanya)

--v3:
- Guard CMRR enable condition (Chaitanya)
- Comment changes updated (Chaitanya)
- Squash register write commits together and
avoid double writing issue. (Chaitanya)

--v4:
- Guard CMRR enable/disable with platform check

--v5:
- Update CMRR in enable/disable path

--v6:
- Simplify enable/disable calls (Chaitanya)
- Make function usable for common cmtg and cpu transcoder
(Chaitanya)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Assisted-by: Claude:claude-opus-4-8
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 59 ++++++++++++++++--------
 1 file changed, 40 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 056d513ab637..8d871aa58cab 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -352,6 +352,36 @@ int intel_vrr_fixed_rr_hw_flipline(const struct intel_crtc_state *crtc_state)
 	return intel_vrr_fixed_rr_hw_vtotal(crtc_state);
 }
 
+static void
+intel_vrr_set_cmrr_timings(const struct intel_crtc_state *crtc_state,
+			   enum transcoder transcoder)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+
+	if (!intel_vrr_cmrr_possible(crtc_state))
+		return;
+
+	intel_de_write(display, TRANS_CMRR_M_HI(display, transcoder),
+		       upper_32_bits(crtc_state->vrr.cmrr.cmrr_m));
+	intel_de_write(display, TRANS_CMRR_M_LO(display, transcoder),
+		       lower_32_bits(crtc_state->vrr.cmrr.cmrr_m));
+	intel_de_write(display, TRANS_CMRR_N_LO(display, transcoder),
+		       lower_32_bits(crtc_state->vrr.cmrr.cmrr_n));
+	intel_de_write(display, TRANS_CMRR_N_HI(display, transcoder),
+		       upper_32_bits(crtc_state->vrr.cmrr.cmrr_n));
+
+	/*
+	 * On always-VRR-TG platforms the fastset path does not rewrite the
+	 * whole TRANS_VRR_CTL, so RMW only the CMRR enable bit here. On a
+	 * modeset the authoritative writes (intel_vrr_tg_enable(),
+	 * intel_cmtg_set_vrr_ctl()) carry the same bit, so this stays
+	 * consistent.
+	 */
+	intel_de_rmw(display, TRANS_VRR_CTL(display, transcoder),
+		     VRR_CTL_CMRR_ENABLE,
+		     crtc_state->vrr.cmrr.enable ? VRR_CTL_CMRR_ENABLE : 0);
+}
+
 void intel_vrr_set_fixed_rr_timings(const struct intel_crtc_state *crtc_state,
 				    enum transcoder transcoder)
 {
@@ -360,6 +390,8 @@ void intel_vrr_set_fixed_rr_timings(const struct intel_crtc_state *crtc_state,
 	if (!intel_vrr_possible(crtc_state))
 		return;
 
+	intel_vrr_set_cmrr_timings(crtc_state, transcoder);
+
 	intel_de_write(display, TRANS_VRR_VMIN(display, transcoder),
 		       intel_vrr_fixed_rr_hw_vmin(crtc_state) - 1);
 	intel_de_write(display, TRANS_VRR_VMAX(display, transcoder),
@@ -671,17 +703,6 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
 		return;
 	}
 
-	if (crtc_state->vrr.cmrr.enable) {
-		intel_de_write(display, TRANS_CMRR_M_HI(display, cpu_transcoder),
-			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_m));
-		intel_de_write(display, TRANS_CMRR_M_LO(display, cpu_transcoder),
-			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_m));
-		intel_de_write(display, TRANS_CMRR_N_HI(display, cpu_transcoder),
-			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_n));
-		intel_de_write(display, TRANS_CMRR_N_LO(display, cpu_transcoder),
-			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_n));
-	}
-
 	intel_vrr_set_fixed_rr_timings(crtc_state, cpu_transcoder);
 	intel_cmtg_set_vrr_timings(crtc_state);
 
@@ -947,8 +968,7 @@ intel_vrr_disable_dc_balancing(const struct intel_crtc_state *old_crtc_state)
 	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder), vrr_ctl);
 }
 
-static void intel_vrr_tg_enable(const struct intel_crtc_state *crtc_state,
-				bool cmrr_enable)
+static void intel_vrr_tg_enable(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_display *display = to_intel_display(crtc_state);
 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
@@ -960,11 +980,12 @@ static void intel_vrr_tg_enable(const struct intel_crtc_state *crtc_state,
 	vrr_ctl = VRR_CTL_VRR_ENABLE | trans_vrr_ctl(crtc_state);
 
 	/*
-	 * FIXME this might be broken as bspec seems to imply that
-	 * even VRR_CTL_CMRR_ENABLE is armed by TRANS_CMRR_N_HI
-	 * when enabling CMRR (but not when disabling CMRR?).
+	 * This full TRANS_VRR_CTL write is the authoritative one, so it must
+	 * carry VRR_CTL_CMRR_ENABLE when CMRR is in use. Writing TRANS_CMRR_N_HI
+	 * arms the bit in hardware, but this later write would otherwise clear
+	 * it again.
 	 */
-	if (cmrr_enable)
+	if (crtc_state->vrr.cmrr.enable)
 		vrr_ctl |= VRR_CTL_CMRR_ENABLE;
 
 	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder), vrr_ctl);
@@ -1000,7 +1021,7 @@ void intel_vrr_enable(const struct intel_crtc_state *crtc_state)
 	intel_vrr_enable_dc_balancing(crtc_state);
 
 	if (!intel_vrr_always_use_vrr_tg(display))
-		intel_vrr_tg_enable(crtc_state, crtc_state->vrr.cmrr.enable);
+		intel_vrr_tg_enable(crtc_state);
 }
 
 void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
@@ -1027,7 +1048,7 @@ void intel_vrr_transcoder_enable(const struct intel_crtc_state *crtc_state)
 		return;
 
 	if (intel_vrr_always_use_vrr_tg(display))
-		intel_vrr_tg_enable(crtc_state, false);
+		intel_vrr_tg_enable(crtc_state);
 }
 
 void intel_vrr_transcoder_disable(const struct intel_crtc_state *old_crtc_state)
-- 
2.48.1

[PATCH v7 09/10] drm/i915/vrr: Dump CMRR state in the crtc state dump

[Mitul Golani]

Add crtc state dump for CMRR.

--v2:
- Remove video mode state checker.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 drivers/gpu/drm/i915/display/intel_crtc_state_dump.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c b/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c
index 4493483f10a9..ad4f362e0c09 100644
--- a/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c
+++ b/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c
@@ -311,6 +311,9 @@ void intel_crtc_state_dump(const struct intel_crtc_state *pipe_config,
 		   pipe_config->vrr.dc_balance.max_increase,
 		   pipe_config->vrr.dc_balance.max_decrease,
 		   pipe_config->vrr.dc_balance.vblank_target);
+	drm_printf(&p, "cmrr: %s, cmrr_m: %llu, cmrr_n: %llu\n",
+		   str_yes_no(pipe_config->vrr.cmrr.enable),
+		   pipe_config->vrr.cmrr.cmrr_m, pipe_config->vrr.cmrr.cmrr_n);
 
 	drm_printf(&p, "requested mode: " DRM_MODE_FMT "\n",
 		   DRM_MODE_ARG(&pipe_config->hw.mode));
-- 
2.48.1

[PATCH v7 10/10] drm/i915/vrr: Enable cmrr

[Mitul Golani]

Enable CMRR during compute config and add related state
checker for the same.

--v2:
- Everything else except enable compute to handle before this patch
(Chaitanya)

--v3:
- Remove redundant return from compute config

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 8d871aa58cab..c17df4675ec1 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -277,6 +277,8 @@ intel_vrr_cmrr_compute_config(struct intel_crtc_state *crtc_state)
 	adjusted_mode->crtc_vtotal = div64_u64_rem(dividend,
 						   crtc_state->vrr.cmrr.cmrr_n,
 						   &crtc_state->vrr.cmrr.cmrr_m);
+
+	crtc_state->vrr.cmrr.enable = true;
 }
 
 static
-- 
2.48.1

[PATCH v8 01/10] drm/i915/vrr: Return from PSR2 compute config in case of CMRR enabled

[Mitul Golani]

CMRR is mutually exclusive to PSR2, do not enable PSR2 when CMRR is
enabled.

--v2:
- Restrict selective update config check (Ankit)
- Commit message change

--v3:
- Commit changes

--v4:
- Add check to psr2_config_valid (Jouni)

--v5:
- Correct debug message

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 40e3d7095996..410778e73a2d 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1491,6 +1491,12 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 	int crtc_vdisplay = crtc_state->hw.adjusted_mode.crtc_vdisplay;
 	int psr_max_h = 0, psr_max_v = 0, max_bpp = 0;
 
+	if (crtc_state->cmrr.enable) {
+		drm_dbg_kms(display->drm,
+			    "PSR2 cannot be enabled when CMRR is enabled\n");
+		return false;
+	}
+
 	if (!connector->dp.psr_caps.su_support || display->params.enable_psr == 1)
 		return false;
 
-- 
2.48.1

✓ i915.CI.BAT: success for Enable CMRR in fixed-RR VRR path (rev7)

[Patchwork]

[-- Attachment #1: Type: text/plain, Size: 4265 bytes --]

== Series Details ==

Series: Enable CMRR in fixed-RR VRR path (rev7)
URL   : https://patchwork.freedesktop.org/series/166819/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_18911 -> Patchwork_166819v7
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/index.html

Participating hosts (40 -> 39)
------------------------------

  Additional (1): bat-adls-6 
  Missing    (2): bat-dg2-13 fi-snb-2520m 

Known issues
------------

  Here are the changes found in Patchwork_166819v7 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@gem_lmem_swapping@parallel-random-engines:
    - bat-adls-6:         NOTRUN -> [SKIP][1] ([i915#4613]) +3 other tests skip
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@gem_lmem_swapping@parallel-random-engines.html

  * igt@gem_tiled_pread_basic@basic:
    - bat-adls-6:         NOTRUN -> [SKIP][2] ([i915#15656])
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@gem_tiled_pread_basic@basic.html

  * igt@intel_hwmon@hwmon-read:
    - bat-adls-6:         NOTRUN -> [SKIP][3] ([i915#7707]) +1 other test skip
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@intel_hwmon@hwmon-read.html

  * igt@kms_cursor_legacy@basic-busy-flip-before-cursor-legacy:
    - bat-adls-6:         NOTRUN -> [SKIP][4] ([i915#4103]) +1 other test skip
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@kms_cursor_legacy@basic-busy-flip-before-cursor-legacy.html

  * igt@kms_dsc@dsc-basic:
    - bat-adls-6:         NOTRUN -> [SKIP][5] ([i915#16361])
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@kms_dsc@dsc-basic.html

  * igt@kms_force_connector_basic@force-load-detect:
    - bat-adls-6:         NOTRUN -> [SKIP][6]
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@kms_force_connector_basic@force-load-detect.html

  * igt@kms_pm_backlight@basic-brightness:
    - bat-adls-6:         NOTRUN -> [SKIP][7] ([i915#5354])
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@kms_pm_backlight@basic-brightness.html

  * igt@kms_psr@psr-primary-mmap-gtt:
    - bat-adls-6:         NOTRUN -> [SKIP][8] ([i915#1072] / [i915#9732]) +3 other tests skip
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@kms_psr@psr-primary-mmap-gtt.html

  * igt@kms_setmode@basic-clone-single-crtc:
    - bat-adls-6:         NOTRUN -> [SKIP][9] ([i915#3555])
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@kms_setmode@basic-clone-single-crtc.html

  * igt@prime_vgem@basic-fence-read:
    - bat-adls-6:         NOTRUN -> [SKIP][10] ([i915#3291]) +2 other tests skip
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/bat-adls-6/igt@prime_vgem@basic-fence-read.html

  
  [i915#1072]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/1072
  [i915#15656]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15656
  [i915#16361]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/16361
  [i915#3291]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/3291
  [i915#3555]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/3555
  [i915#4103]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/4103
  [i915#4613]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/4613
  [i915#5354]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/5354
  [i915#7707]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/7707
  [i915#9732]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/9732


Build changes
-------------

  * Linux: CI_DRM_18911 -> Patchwork_166819v7

  CI-20190529: 20190529
  CI_DRM_18911: 231ba00442a06ee877bfed4765c0b1b48bebbf78 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_9027: 9027
  Patchwork_166819v7: 231ba00442a06ee877bfed4765c0b1b48bebbf78 @ git://anongit.freedesktop.org/gfx-ci/linux

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v7/index.html

[-- Attachment #2: Type: text/html, Size: 5113 bytes --]

✓ i915.CI.BAT: success for Enable CMRR in fixed-RR VRR path (rev8)

[Patchwork]

[-- Attachment #1: Type: text/plain, Size: 4265 bytes --]

== Series Details ==

Series: Enable CMRR in fixed-RR VRR path (rev8)
URL   : https://patchwork.freedesktop.org/series/166819/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_18911 -> Patchwork_166819v8
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/index.html

Participating hosts (40 -> 39)
------------------------------

  Additional (1): bat-adls-6 
  Missing    (2): bat-dg2-13 fi-snb-2520m 

Known issues
------------

  Here are the changes found in Patchwork_166819v8 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@gem_lmem_swapping@parallel-random-engines:
    - bat-adls-6:         NOTRUN -> [SKIP][1] ([i915#4613]) +3 other tests skip
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@gem_lmem_swapping@parallel-random-engines.html

  * igt@gem_tiled_pread_basic@basic:
    - bat-adls-6:         NOTRUN -> [SKIP][2] ([i915#15656])
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@gem_tiled_pread_basic@basic.html

  * igt@intel_hwmon@hwmon-read:
    - bat-adls-6:         NOTRUN -> [SKIP][3] ([i915#7707]) +1 other test skip
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@intel_hwmon@hwmon-read.html

  * igt@kms_cursor_legacy@basic-busy-flip-before-cursor-legacy:
    - bat-adls-6:         NOTRUN -> [SKIP][4] ([i915#4103]) +1 other test skip
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@kms_cursor_legacy@basic-busy-flip-before-cursor-legacy.html

  * igt@kms_dsc@dsc-basic:
    - bat-adls-6:         NOTRUN -> [SKIP][5] ([i915#16361])
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@kms_dsc@dsc-basic.html

  * igt@kms_force_connector_basic@force-load-detect:
    - bat-adls-6:         NOTRUN -> [SKIP][6]
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@kms_force_connector_basic@force-load-detect.html

  * igt@kms_pm_backlight@basic-brightness:
    - bat-adls-6:         NOTRUN -> [SKIP][7] ([i915#5354])
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@kms_pm_backlight@basic-brightness.html

  * igt@kms_psr@psr-primary-mmap-gtt:
    - bat-adls-6:         NOTRUN -> [SKIP][8] ([i915#1072] / [i915#9732]) +3 other tests skip
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@kms_psr@psr-primary-mmap-gtt.html

  * igt@kms_setmode@basic-clone-single-crtc:
    - bat-adls-6:         NOTRUN -> [SKIP][9] ([i915#3555])
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@kms_setmode@basic-clone-single-crtc.html

  * igt@prime_vgem@basic-fence-read:
    - bat-adls-6:         NOTRUN -> [SKIP][10] ([i915#3291]) +2 other tests skip
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/bat-adls-6/igt@prime_vgem@basic-fence-read.html

  
  [i915#1072]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/1072
  [i915#15656]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15656
  [i915#16361]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/16361
  [i915#3291]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/3291
  [i915#3555]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/3555
  [i915#4103]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/4103
  [i915#4613]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/4613
  [i915#5354]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/5354
  [i915#7707]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/7707
  [i915#9732]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/9732


Build changes
-------------

  * Linux: CI_DRM_18911 -> Patchwork_166819v8

  CI-20190529: 20190529
  CI_DRM_18911: 231ba00442a06ee877bfed4765c0b1b48bebbf78 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_9027: 9027
  Patchwork_166819v8: 231ba00442a06ee877bfed4765c0b1b48bebbf78 @ git://anongit.freedesktop.org/gfx-ci/linux

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_166819v8/index.html

[-- Attachment #2: Type: text/html, Size: 5113 bytes --]

Re: [PATCH v8 01/10] drm/i915/vrr: Return from PSR2 compute config in case of CMRR enabled

[Borah, Chaitanya Kumar]

On 7/28/2026 8:53 PM, Mitul Golani wrote:
> CMRR is mutually exclusive to PSR2, do not enable PSR2 when CMRR is
> enabled.
> 

nit: drm/i915/psr: Do not enable PSR2 when CMRR is ON

With that,

Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
> --v2:
> - Restrict selective update config check (Ankit)
> - Commit message change
> 
> --v3:
> - Commit changes
> 
> --v4:
> - Add check to psr2_config_valid (Jouni)
> 
> --v5:
> - Correct debug message
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_psr.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 40e3d7095996..410778e73a2d 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -1491,6 +1491,12 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>   	int crtc_vdisplay = crtc_state->hw.adjusted_mode.crtc_vdisplay;
>   	int psr_max_h = 0, psr_max_v = 0, max_bpp = 0;
>   
> +	if (crtc_state->cmrr.enable) {
> +		drm_dbg_kms(display->drm,
> +			    "PSR2 cannot be enabled when CMRR is enabled\n");
> +		return false;
> +	}
> +
>   	if (!connector->dp.psr_caps.su_support || display->params.enable_psr == 1)
>   		return false;
>   

Re: [PATCH v7 05/10] drm/i915/display: Move CMRR crtc_state members under VRR

[Borah, Chaitanya Kumar]

On 7/28/2026 8:29 PM, Mitul Golani wrote:
> Move CMRR crtc state members under VRR infrastructure as
> it is enabled during fixed-refresh-rate VRR timing generator
> is enabled.
> 
> --v2:
> - Move cmrr structure under vrr umbrella.
> - Remove dups. (Jani)
> 
> --v3:
> - Update commit message
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_cmtg.c     |  2 +-
>   drivers/gpu/drm/i915/display/intel_display.c  | 10 +++----
>   .../drm/i915/display/intel_display_types.h    | 12 ++++----
>   drivers/gpu/drm/i915/display/intel_dp.c       |  2 +-
>   drivers/gpu/drm/i915/display/intel_psr.c      |  2 +-
>   drivers/gpu/drm/i915/display/intel_vrr.c      | 30 +++++++++----------
>   6 files changed, 29 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.c b/drivers/gpu/drm/i915/display/intel_cmtg.c
> index c8e0f90af910..3c0f5b2fb2e7 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.c
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.c
> @@ -326,7 +326,7 @@ void intel_cmtg_set_vrr_ctl(const struct intel_crtc_state *crtc_state)
>   		  XELPD_VRR_CTL_VRR_GUARDBAND(crtc_state->vrr.guardband);
>   
>   	/* TODO: The code below may need to be revisited once CMRR is enabled */
> -	if (crtc_state->cmrr.enable)
> +	if (crtc_state->vrr.cmrr.enable)
>   		vrr_ctl |= VRR_CTL_CMRR_ENABLE;
>   
>   	intel_de_write(display, TRANS_VRR_CTL(display, cmtg_transcoder), vrr_ctl);
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 9dfd095f325f..8ce762188665 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -950,8 +950,8 @@ static bool vrr_params_changed(const struct intel_crtc_state *old_crtc_state,
>   static bool cmrr_params_changed(const struct intel_crtc_state *old_crtc_state,
>   				const struct intel_crtc_state *new_crtc_state)
>   {
> -	return old_crtc_state->cmrr.cmrr_m != new_crtc_state->cmrr.cmrr_m ||
> -		old_crtc_state->cmrr.cmrr_n != new_crtc_state->cmrr.cmrr_n;
> +	return old_crtc_state->vrr.cmrr.cmrr_m != new_crtc_state->vrr.cmrr.cmrr_m ||
> +		old_crtc_state->vrr.cmrr.cmrr_n != new_crtc_state->vrr.cmrr.cmrr_n;
>   }
>   
>   static bool intel_crtc_vrr_enabling(struct intel_atomic_state *state,
> @@ -5536,9 +5536,9 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>   		PIPE_CONF_CHECK_I(vrr.flipline);
>   		PIPE_CONF_CHECK_I(vrr.vsync_start);
>   		PIPE_CONF_CHECK_I(vrr.vsync_end);
> -		PIPE_CONF_CHECK_LLI(cmrr.cmrr_m);
> -		PIPE_CONF_CHECK_LLI(cmrr.cmrr_n);
> -		PIPE_CONF_CHECK_BOOL(cmrr.enable);
> +		PIPE_CONF_CHECK_LLI(vrr.cmrr.cmrr_m);
> +		PIPE_CONF_CHECK_LLI(vrr.cmrr.cmrr_n);
> +		PIPE_CONF_CHECK_BOOL(vrr.cmrr.enable);
>   		PIPE_CONF_CHECK_I(vrr.dc_balance.vmin);
>   		PIPE_CONF_CHECK_I(vrr.dc_balance.vmax);
>   		PIPE_CONF_CHECK_I(vrr.dc_balance.guardband);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 46dd980b315a..20a07ea06b5e 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1408,13 +1408,13 @@ struct intel_crtc_state {
>   			u16 max_increase, max_decrease;
>   			u16 vblank_target;
>   		} dc_balance;
> -	} vrr;
>   
> -	/* Content Match Refresh Rate state */
> -	struct {
> -		bool enable;
> -		u64 cmrr_n, cmrr_m;
> -	} cmrr;
> +		/* Content Match Refresh Rate state */
> +		struct {
> +			bool enable;
> +			u64 cmrr_n, cmrr_m;
> +		} cmrr;
> +	} vrr;
>   
>   	/* Stream Splitter for eDP MSO */
>   	struct {
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 9e2db310b7d8..7f13595f40c1 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3143,7 +3143,7 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
>   	as_sdp->revision = 0x2;
>   	as_sdp->vtotal = intel_vrr_vmin_vtotal(crtc_state);
>   
> -	if (crtc_state->cmrr.enable) {
> +	if (crtc_state->vrr.cmrr.enable) {
>   		as_sdp->mode = DP_AS_SDP_FAVT_TRR_REACHED;
>   		as_sdp->target_rr = drm_mode_vrefresh(adjusted_mode);
>   
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 5ddcede6db27..d2009e317024 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -1491,7 +1491,7 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>   	int crtc_vdisplay = crtc_state->hw.adjusted_mode.crtc_vdisplay;
>   	int psr_max_h = 0, psr_max_v = 0, max_bpp = 0;
>   
> -	if (crtc_state->cmrr.enable) {
> +	if (crtc_state->vrr.cmrr.enable) {
>   		drm_dbg_kms(display->drm,
>   			    "Selective update cannot be enabled when CMRR is enabled\n");

The log was changed in Patch 1 so this does not apply anymore.

>   		return false;
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 615c8fa8c063..6d3333fd5281 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -235,12 +235,12 @@ cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool video_mode_required)
>   		multiplier_n = 1000;
>   	}
>   
> -	crtc_state->cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
> -					      multiplier_n);
> +	crtc_state->vrr.cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
> +						  multiplier_n);
>   	vtotal = DIV_ROUND_UP_ULL(mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_n),
> -				  crtc_state->cmrr.cmrr_n);
> +				  crtc_state->vrr.cmrr.cmrr_n);
>   	adjusted_pixel_rate = mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_m);
> -	crtc_state->cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->cmrr.cmrr_n);
> +	crtc_state->vrr.cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->vrr.cmrr.cmrr_n);
>   
>   	return vtotal;
>   }
> @@ -258,7 +258,7 @@ void intel_vrr_compute_cmrr_timings(struct intel_crtc_state *crtc_state)
>   	crtc_state->vrr.vmin = crtc_state->vrr.vmax;
>   	crtc_state->vrr.flipline = crtc_state->vrr.vmin;
>   
> -	crtc_state->cmrr.enable = true;
> +	crtc_state->vrr.cmrr.enable = true;
>   	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
>   }
>   
> @@ -651,15 +651,15 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
>   		return;
>   	}
>   
> -	if (crtc_state->cmrr.enable) {
> +	if (crtc_state->vrr.cmrr.enable) {
>   		intel_de_write(display, TRANS_CMRR_M_HI(display, cpu_transcoder),
> -			       upper_32_bits(crtc_state->cmrr.cmrr_m));
> +			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_m));
>   		intel_de_write(display, TRANS_CMRR_M_LO(display, cpu_transcoder),
> -			       lower_32_bits(crtc_state->cmrr.cmrr_m));
> +			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_m));
>   		intel_de_write(display, TRANS_CMRR_N_HI(display, cpu_transcoder),
> -			       upper_32_bits(crtc_state->cmrr.cmrr_n));
> +			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_n));
>   		intel_de_write(display, TRANS_CMRR_N_LO(display, cpu_transcoder),
> -			       lower_32_bits(crtc_state->cmrr.cmrr_n));
> +			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_n));
>   	}
>   
>   	intel_vrr_set_fixed_rr_timings(crtc_state, cpu_transcoder);
> @@ -980,7 +980,7 @@ void intel_vrr_enable(const struct intel_crtc_state *crtc_state)
>   	intel_vrr_enable_dc_balancing(crtc_state);
>   
>   	if (!intel_vrr_always_use_vrr_tg(display))
> -		intel_vrr_tg_enable(crtc_state, crtc_state->cmrr.enable);
> +		intel_vrr_tg_enable(crtc_state, crtc_state->vrr.cmrr.enable);
>   }
>   
>   void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
> @@ -1077,12 +1077,12 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
>   				      TRANS_VRR_CTL(display, cpu_transcoder));
>   
>   	if (intel_vrr_cmrr_possible(crtc_state))
> -		crtc_state->cmrr.enable = (trans_vrr_ctl & VRR_CTL_CMRR_ENABLE);
> +		crtc_state->vrr.cmrr.enable = (trans_vrr_ctl & VRR_CTL_CMRR_ENABLE);
>   
> -	if (crtc_state->cmrr.enable) {
> -		crtc_state->cmrr.cmrr_n =
> +	if (crtc_state->vrr.cmrr.enable) {
> +		crtc_state->vrr.cmrr.cmrr_n =
>   			intel_de_read64_2x32(display, TRANS_CMRR_N_LO(display, cpu_transcoder));
> -		crtc_state->cmrr.cmrr_m =
> +		crtc_state->vrr.cmrr.cmrr_m =
>   			intel_de_read64_2x32(display, TRANS_CMRR_M_LO(display, cpu_transcoder));
>   	}
>   

Re: [PATCH v7 06/10] drm/i915/vrr: Compute CMRR fractional timings generically

[Borah, Chaitanya Kumar]

On 7/28/2026 8:29 PM, Mitul Golani wrote:
> Rework the fractional CMRR computation into a generic,
> transcoder-agnostic helper driven by an explicit per-CRTC debugfs
> target, replacing the previous disabled, eDP-only code path. Compute
> CMRR_M and CMRR_N timings based on the video mode requirements. Note
> that the CMRR enable path is wired up separately; this patch only lays
> down the generic computation. Remove computation of mode_flags,
> I915_MODE_FLAG_VRR, as CMRR is being moved to the fixed refresh rate
> path. Also return early from the CMRR computation if the existing
> computation is already sufficient.
> 
> --v2:
> - Derive video_mode locally instead of caching it in the persistent
>    struct intel_crtc state (Jani, Chaitanya)
> - Fix numerator unit in comment: milli-Hz, not kHz (Chaitanya)
> - Fix "requirement" typo and clarify that CMRR is not yet enabled in
>    the commit message (Chaitanya)
> - Fix precision issue while computing the M/N ratio (Chaitanya)
> - Rename multiplier_m and multiplier_n to improve readability
>    (Chaitanya)
> - Compute vtotal as it is required for dithering as per the algorithm
>    implementation (Chaitanya)
> - Replace the misleading adjusted_pixel_rate with dividend, which is
>    more descriptive
> 
> --v3:
> - Mention the rationale for not computing I915_MODE_FLAG_VRR
>    (Chaitanya)
> - Remove the redundant return statement at the end of the CMRR
>    computation (Chaitanya)
> - Correct cmrr_n calculation (Chaitanya)
> - Add an early return if the current computation is already sufficient
>    to drive the mode without CMRR (Chaitanya)
> - Round up requested_refresh_rate (Validation)
> - Fix integer overflow
> 
> --v4:
> - Update cmrr_n calculation to avoid aggressive dithering
> - Use div64_u64 to truncate to the floor value instead of
>    DIV_ROUND_UP_ULL, which rounds up to the ceiling value
> - Add a TODO comment to the cmrr_n calculation
> - Add a condition for custom refresh rate requests
> - Update the CMRR computation comment block in compute_config
> 
> --v5:
> - Simplify computation
> - Correct typo in commit message (Chaitanya)
> - Compute early return condition (Chaitanya)
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_vrr.c | 143 ++++++++++++-----------
>   1 file changed, 78 insertions(+), 65 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 6d3333fd5281..7746b2ead7d1 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -27,9 +27,6 @@
>   #include "skl_prefill.h"
>   #include "skl_watermark.h"
>   
> -#define FIXED_POINT_PRECISION		100
> -#define CMRR_PRECISION_TOLERANCE	10
> -
>   /*
>    * Tunable parameters for DC Balance correction.
>    * These are captured based on experimentations.
> @@ -198,68 +195,86 @@ static bool intel_vrr_cmrr_possible(const struct intel_crtc_state *crtc_state)
>   	return HAS_CMRR(display) && intel_vrr_always_use_vrr_tg(display);
>   }
>   
> -static bool
> -is_cmrr_frac_required(struct intel_crtc_state *crtc_state)
> +static void
> +intel_vrr_cmrr_compute_config(struct intel_crtc_state *crtc_state)
>   {
> -	int calculated_refresh_k, actual_refresh_k, pixel_clock_per_line;
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>   	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> +	u64 dividend;
> +	u32 mode_rate_mhz;
> +	u32 requested_rate_mhz = crtc->force_cmrr.numerator;
> +	int rr_multiplier = 1, rr_divider = 1;
>   
> -	/* Avoid CMRR for now till we have VRR with fixed timings working */
> -	if (!intel_vrr_cmrr_possible(crtc_state) || true)
> -		return false;
> -
> -	actual_refresh_k =
> -		drm_mode_vrefresh(adjusted_mode) * FIXED_POINT_PRECISION;
> -	pixel_clock_per_line =
> -		adjusted_mode->crtc_clock * 1000 / adjusted_mode->crtc_htotal;
> -	calculated_refresh_k =
> -		pixel_clock_per_line * FIXED_POINT_PRECISION / adjusted_mode->crtc_vtotal;
> -
> -	if ((actual_refresh_k - calculated_refresh_k) < CMRR_PRECISION_TOLERANCE)
> -		return false;
> -
> -	return true;
> -}
> -
> -static unsigned int
> -cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool video_mode_required)
> -{
> -	int multiplier_m = 1, multiplier_n = 1, vtotal, desired_refresh_rate;
> -	u64 adjusted_pixel_rate;
> -	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> +	if (!intel_vrr_cmrr_possible(crtc_state))
> +		return;
>   
> -	desired_refresh_rate = drm_mode_vrefresh(adjusted_mode);
> +	/* No CMRR ratio configured through debugfs */
> +	if (!requested_rate_mhz)
> +		return;
>   
> -	if (video_mode_required) {
> -		multiplier_m = 1001;
> -		multiplier_n = 1000;
> +	/* Requested rate must match the mode's nominal (integer) refresh rate */
> +	if (DIV_ROUND_CLOSEST(requested_rate_mhz, 1000) !=
> +			drm_mode_vrefresh(adjusted_mode)) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] CMRR requested %u.%03u Hz doesn't match mode %d Hz\n",
> +			    crtc->base.base.id, crtc->base.name,
> +			    requested_rate_mhz / 1000, requested_rate_mhz % 1000,
> +			    drm_mode_vrefresh(adjusted_mode));
> +		return;
>   	}
>   
> -	crtc_state->vrr.cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
> -						  multiplier_n);
> -	vtotal = DIV_ROUND_UP_ULL(mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_n),
> -				  crtc_state->vrr.cmrr.cmrr_n);
> -	adjusted_pixel_rate = mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_m);
> -	crtc_state->vrr.cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->vrr.cmrr.cmrr_n);
> -
> -	return vtotal;
> -}
> +	/* Actual rate produced by the current timings, in milli-Hz */
> +	mode_rate_mhz =
> +		DIV_ROUND_CLOSEST_ULL((u64)adjusted_mode->crtc_clock * 1000 * 1000,
> +				      adjusted_mode->crtc_vtotal *
> +				      adjusted_mode->crtc_htotal);
>   
> -static
> -void intel_vrr_compute_cmrr_timings(struct intel_crtc_state *crtc_state)
> -{
>   	/*
> -	 * TODO: Compute precise target refresh rate to determine
> -	 * if video_mode_required should be true. Currently set to
> -	 * false due to uncertainty about the precise target
> -	 * refresh Rate.
> +	 * A 1:1 ratio (denominator == 1000) means no video timing is required
> +	 * Any other ratio (e.g. 1000/1001) requires the video timing.
>   	 */
> -	crtc_state->vrr.vmax = cmrr_get_vtotal(crtc_state, false);
> -	crtc_state->vrr.vmin = crtc_state->vrr.vmax;
> -	crtc_state->vrr.flipline = crtc_state->vrr.vmin;
> +	if (crtc->force_cmrr.denominator == 1000) {
> +		rr_multiplier = 1;
> +		rr_divider = 1;
> +

This assigment is redundant. We could perhaps do something on the lines of

bool video_mode = crtc->force_cmrr.denominator != 1000;
int rr_multiplier = video_mode ? 1000 : 1;
int rr_divider    = video_mode ? 1001 : 1;
...
/* 1:1 request already satisfied by the mode -> CMRR not needed */
if (!video_mode &&
     DIV_ROUND_CLOSEST(mode_rate_mhz, 10) == 
DIV_ROUND_CLOSEST(requested_rate_mhz, 10)) {
     drm_dbg_kms(...);
     return;
}


Eventually, we need to make the interface more generic instead of relyng 
explicitly on fixed denominator values but that is for another day.

So for now,

Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>

> +		/* Mode already hits the exact rate -> CMRR not needed */
> +		if (DIV_ROUND_CLOSEST(mode_rate_mhz, 10) ==
> +		    DIV_ROUND_CLOSEST(requested_rate_mhz, 10)) {
> +			drm_dbg_kms(display->drm,
> +				    "[CRTC:%d:%s] %u.%03u Hz can be driven without CMRR\n",
> +				    crtc->base.base.id, crtc->base.name,
> +				    requested_rate_mhz / 1000, requested_rate_mhz % 1000);
> +			return;
> +		}
> +	} else {
> +		rr_multiplier = 1000;
> +		rr_divider = 1001;
> +	}
>   
> -	crtc_state->vrr.cmrr.enable = true;
> -	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
> +	/*
> +	 * Let pixel_clock_hz = adjusted_mode->crtc_clock * 1000.
> +	 *
> +	 * cmrr_n = (requested_rate_mhz x htotal x rr_multiplier) / 1000
> +	 * cmrr_m = (pixel_clock_hz x rr_divider) % cmrr_n
> +	 *
> +	 * where requested_rate_mhz is the requested refresh rate in milli-Hz
> +	 * and rr_multiplier/rr_divider = 1000/1001 when the video timing
> +	 * is required, else 1/1. The integer vtotal term is tracked in SW
> +	 * (it is the programmed mode vtotal) while the fractional part
> +	 * represented by cmrr_m/cmrr_n is tracked in HW.
> +	 *
> +	 * TODO: Using the actual desired rate for cmrr_n in video
> +	 * mode produces more aggressive vtotal dithering than
> +	 * expected; revisit once the Bspec algorithm is clarified.
> +	 */
> +	crtc_state->vrr.cmrr.cmrr_n =
> +		div64_u64((u64)requested_rate_mhz *
> +			  adjusted_mode->crtc_htotal * rr_multiplier, 1000);
> +	dividend = (u64)adjusted_mode->crtc_clock * rr_divider * 1000;
> +	adjusted_mode->crtc_vtotal = div64_u64_rem(dividend,
> +						   crtc_state->vrr.cmrr.cmrr_n,
> +						   &crtc_state->vrr.cmrr.cmrr_m);
>   }
>   
>   static
> @@ -435,8 +450,6 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
>   	struct intel_display *display = to_intel_display(crtc_state);
>   	struct intel_connector *connector =
>   		to_intel_connector(conn_state->connector);
> -	struct intel_dp *intel_dp = intel_attached_dp(connector);
> -	bool is_edp = intel_dp_is_edp(intel_dp);
>   	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
>   	int vmin, vmax;
>   
> @@ -470,12 +483,17 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
>   		vmax = vmin;
>   	}
>   
> -	if (crtc_state->uapi.vrr_enabled && vmin < vmax)
> +	if (crtc_state->uapi.vrr_enabled && vmin < vmax) {
>   		intel_vrr_compute_vrr_timings(crtc_state, vmin, vmax);
> -	else if (is_cmrr_frac_required(crtc_state) && is_edp)
> -		intel_vrr_compute_cmrr_timings(crtc_state);
> -	else
> +	} else {
> +		/*
> +		 * CMRR is a fixed average Vtotal mode and is only computed on
> +		 * the fixed refresh rate path. It is generic across transcoders
> +		 * and gated on platform support and a valid debugfs ratio.
> +		 */
> +		intel_vrr_cmrr_compute_config(crtc_state);
>   		intel_vrr_compute_fixed_rr_timings(crtc_state);
> +	}
>   
>   	if (HAS_AS_SDP(display)) {
>   		crtc_state->vrr.vsync_start =
> @@ -1142,11 +1160,6 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
>   
>   	intel_vrr_get_dc_balance_config(crtc_state);
>   
> -	/*
> -	 * #TODO: For Both VRR and CMRR the flag I915_MODE_FLAG_VRR is set for mode_flags.
> -	 * Since CMRR is currently disabled, set this flag for VRR for now.
> -	 * Need to keep this in mind while re-enabling CMRR.
> -	 */
>   	if (crtc_state->vrr.enable)
>   		crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
>   

Re: [PATCH v7 07/10] drm/i915/vrr: Latch CMRR ratio via fastset on debugfs write

[Borah, Chaitanya Kumar]

On 7/28/2026 8:29 PM, Mitul Golani wrote:
> Writing the per-CRTC "intel_vrr_target_refresh_rate" debugfs file only
> updates crtc->force_cmrr, a side channel that is not tracked by the
> atomic state. The requested ratio therefore does not reach the hardware
> until some unrelated commit recomputes the pipe config.
> 
> Kick an internal atomic commit for the CRTC from the debugfs write and
> mark the CRTC mode as changed so the pipe config is recomputed.
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_vrr.c | 63 ++++++++++++++++++++++++
>   1 file changed, 63 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 7746b2ead7d1..056d513ab637 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -8,10 +8,12 @@
>   #include <linux/seq_file.h>
>   #include <linux/string.h>
>   
> +#include <drm/drm_atomic.h>
>   #include <drm/drm_print.h>
>   #include <drm/intel/step.h>
>   
>   #include "intel_alpm.h"
> +#include "intel_atomic.h"
>   #include "intel_cmtg.h"
>   #include "intel_crtc.h"
>   #include "intel_de.h"
> @@ -1312,6 +1314,58 @@ static int intel_vrr_debugfs_target_rr_open(struct inode *inode, struct file *fi
>   	return single_open(file, intel_vrr_debugfs_target_rr_show, inode->i_private);
>   }
>   
> +/*
> + * Force an internal fastset commit on @crtc so that a CMRR ratio programmed
> + * via debugfs gets recomputed and latched into hardware. CMRR only alters the
> + * (average) vtotal, which is handled by the LRR fastset path, so this does not
> + * trigger a full modeset (no blank out).
> + */
> +static int intel_vrr_cmrr_fastset_force(struct intel_crtc *crtc)

We need to be careful with the wording here. This commit may or may not 
be downgraded to a fastset, depending on whether the computed vblank 
value (with LRR disabled) changes. We need to figure out if we can also 
seamlessly change Vtotal in case of CMRR but until then lets not 
characterise it as a fastset commit. Let's just call it a commit.

> +{
> +	struct intel_display *display = to_intel_display(crtc);
> +	struct drm_modeset_acquire_ctx ctx;
> +	struct drm_atomic_commit *state;
> +	struct intel_crtc_state *crtc_state;
> +	int ret = 0;
> +
> +	state = drm_atomic_commit_alloc(display->drm);
> +	if (!state)
> +		return -ENOMEM;
> +
> +	drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE);
> +
> +	state->acquire_ctx = &ctx;
> +	to_intel_atomic_state(state)->internal = true;
> +
> +retry:
> +	crtc_state = intel_atomic_get_crtc_state(state, crtc);
> +	if (IS_ERR(crtc_state)) {
> +		ret = PTR_ERR(crtc_state);
> +		goto out;
> +	}
> +
> +	if (!crtc_state->hw.active)
> +		goto out;
> +
> +	/* Mark mode as changed to trigger a pipe recompute + update() */
> +	crtc_state->uapi.mode_changed = true;
> +
> +	ret = drm_atomic_commit(state);
> +out:
> +	if (ret == -EDEADLK) {
> +		drm_atomic_commit_clear(state);
> +		ret = drm_modeset_backoff(&ctx);
> +		if (!ret)
> +			goto retry;
> +	}
> +
> +	drm_modeset_drop_locks(&ctx);
> +	drm_modeset_acquire_fini(&ctx);
> +	drm_atomic_commit_put(state);
> +
> +	return ret;
> +}
> +
>   static ssize_t intel_vrr_debugfs_target_rr_write(struct file *file, const char __user *ubuf,
>   						 size_t len, loff_t *offp)
>   {
> @@ -1340,6 +1394,15 @@ static ssize_t intel_vrr_debugfs_target_rr_write(struct file *file, const char _
>   	crtc->force_cmrr.numerator = numerator;
>   	crtc->force_cmrr.denominator = denominator;
>   
> +	/*
> +	 * The debugfs value is a side channel that is not tracked by the atomic
> +	 * state, so kick an internal fastset commit to recompute and latch the
> +	 * new CMRR parameters without a full modeset.
> +	 */
> +	ret = intel_vrr_cmrr_fastset_force(crtc);
> +	if (ret)
> +		return ret;
> +

restore the values of num/den to last successful value on failure. 
Otherwise, all subsequent commits fail as force_cmrr holds on to bad values.

>   	return len;
>   }
>   

Re: [PATCH v7 08/10] drm/i915/vrr: Program CMRR enable/disable from transcoder timings

[Borah, Chaitanya Kumar]

On 7/28/2026 8:29 PM, Mitul Golani wrote:
> Split the CMRR M/N register programming into intel_vrr_enable_cmrr()
> and intel_vrr_disable_cmrr(), and drive them from
> intel_vrr_set_fixed_rr_timings() based on crtc_state->vrr.cmrr.enable.
> 

stale commit messageg

> VRR_CTL_CMRR_ENABLE is not set explicitly, writing TRANS_CMRR_N_HI
> arms CMRR in hardware. Drop the now-unused cmrr_enable
> argument to intel_vrr_tg_enable().
> 
> No functional change intended for non-CMRR configurations.
> 
> --v2:
> - Commit message changes.
> - Added Simplified enable/disable sequence. (Chaitanya)
> 
> --v3:
> - Guard CMRR enable condition (Chaitanya)
> - Comment changes updated (Chaitanya)
> - Squash register write commits together and
> avoid double writing issue. (Chaitanya)
> 
> --v4:
> - Guard CMRR enable/disable with platform check
> 
> --v5:
> - Update CMRR in enable/disable path
> 
> --v6:
> - Simplify enable/disable calls (Chaitanya)
> - Make function usable for common cmtg and cpu transcoder
> (Chaitanya)
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> Assisted-by: Claude:claude-opus-4-8
> ---
>   drivers/gpu/drm/i915/display/intel_vrr.c | 59 ++++++++++++++++--------
>   1 file changed, 40 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 056d513ab637..8d871aa58cab 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -352,6 +352,36 @@ int intel_vrr_fixed_rr_hw_flipline(const struct intel_crtc_state *crtc_state)
>   	return intel_vrr_fixed_rr_hw_vtotal(crtc_state);
>   }
>   
> +static void
> +intel_vrr_set_cmrr_timings(const struct intel_crtc_state *crtc_state,
> +			   enum transcoder transcoder)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +
> +	if (!intel_vrr_cmrr_possible(crtc_state))
> +		return;
> +
> +	intel_de_write(display, TRANS_CMRR_M_HI(display, transcoder),
> +		       upper_32_bits(crtc_state->vrr.cmrr.cmrr_m));
> +	intel_de_write(display, TRANS_CMRR_M_LO(display, transcoder),
> +		       lower_32_bits(crtc_state->vrr.cmrr.cmrr_m));
> +	intel_de_write(display, TRANS_CMRR_N_LO(display, transcoder),
> +		       lower_32_bits(crtc_state->vrr.cmrr.cmrr_n));
> +	intel_de_write(display, TRANS_CMRR_N_HI(display, transcoder),
> +		       upper_32_bits(crtc_state->vrr.cmrr.cmrr_n));
> +
> +	/*
> +	 * On always-VRR-TG platforms the fastset path does not rewrite the
> +	 * whole TRANS_VRR_CTL, so RMW only the CMRR enable bit here. On a
> +	 * modeset the authoritative writes (intel_vrr_tg_enable(),
> +	 * intel_cmtg_set_vrr_ctl()) carry the same bit, so this stays
> +	 * consistent.
> +	 */
> +	intel_de_rmw(display, TRANS_VRR_CTL(display, transcoder),
> +		     VRR_CTL_CMRR_ENABLE,
> +		     crtc_state->vrr.cmrr.enable ? VRR_CTL_CMRR_ENABLE : 0);
> +}
> +
>   void intel_vrr_set_fixed_rr_timings(const struct intel_crtc_state *crtc_state,
>   				    enum transcoder transcoder)
>   {
> @@ -360,6 +390,8 @@ void intel_vrr_set_fixed_rr_timings(const struct intel_crtc_state *crtc_state,
>   	if (!intel_vrr_possible(crtc_state))
>   		return;
>   
> +	intel_vrr_set_cmrr_timings(crtc_state, transcoder);
> +
>   	intel_de_write(display, TRANS_VRR_VMIN(display, transcoder),
>   		       intel_vrr_fixed_rr_hw_vmin(crtc_state) - 1);
>   	intel_de_write(display, TRANS_VRR_VMAX(display, transcoder),
> @@ -671,17 +703,6 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
>   		return;
>   	}
>   
> -	if (crtc_state->vrr.cmrr.enable) {
> -		intel_de_write(display, TRANS_CMRR_M_HI(display, cpu_transcoder),
> -			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_m));
> -		intel_de_write(display, TRANS_CMRR_M_LO(display, cpu_transcoder),
> -			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_m));
> -		intel_de_write(display, TRANS_CMRR_N_HI(display, cpu_transcoder),
> -			       upper_32_bits(crtc_state->vrr.cmrr.cmrr_n));
> -		intel_de_write(display, TRANS_CMRR_N_LO(display, cpu_transcoder),
> -			       lower_32_bits(crtc_state->vrr.cmrr.cmrr_n));
> -	}
> -
>   	intel_vrr_set_fixed_rr_timings(crtc_state, cpu_transcoder);
>   	intel_cmtg_set_vrr_timings(crtc_state);
>   
> @@ -947,8 +968,7 @@ intel_vrr_disable_dc_balancing(const struct intel_crtc_state *old_crtc_state)
>   	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder), vrr_ctl);
>   }
>   
> -static void intel_vrr_tg_enable(const struct intel_crtc_state *crtc_state,
> -				bool cmrr_enable)
> +static void intel_vrr_tg_enable(const struct intel_crtc_state *crtc_state)
>   {
>   	struct intel_display *display = to_intel_display(crtc_state);
>   	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> @@ -960,11 +980,12 @@ static void intel_vrr_tg_enable(const struct intel_crtc_state *crtc_state,
>   	vrr_ctl = VRR_CTL_VRR_ENABLE | trans_vrr_ctl(crtc_state);
>   
>   	/*
> -	 * FIXME this might be broken as bspec seems to imply that
> -	 * even VRR_CTL_CMRR_ENABLE is armed by TRANS_CMRR_N_HI
> -	 * when enabling CMRR (but not when disabling CMRR?).

Please add the reasoning for removal of this comment in the commit 
message. The comment below is not a direct replacement. I think the 
experiments show that writing VRR_CTL_CMRR_ENABLE after TRANS_CMRR_N_HI 
works so the comment is not valid anymore.

Other than that, LGTM

Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>

> +	 * This full TRANS_VRR_CTL write is the authoritative one, so it must
> +	 * carry VRR_CTL_CMRR_ENABLE when CMRR is in use. Writing TRANS_CMRR_N_HI
> +	 * arms the bit in hardware, but this later write would otherwise clear
> +	 * it again.
>   	 */
> -	if (cmrr_enable)
> +	if (crtc_state->vrr.cmrr.enable)
>   		vrr_ctl |= VRR_CTL_CMRR_ENABLE;
>   
>   	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder), vrr_ctl);
> @@ -1000,7 +1021,7 @@ void intel_vrr_enable(const struct intel_crtc_state *crtc_state)
>   	intel_vrr_enable_dc_balancing(crtc_state);
>   
>   	if (!intel_vrr_always_use_vrr_tg(display))
> -		intel_vrr_tg_enable(crtc_state, crtc_state->vrr.cmrr.enable);
> +		intel_vrr_tg_enable(crtc_state);
>   }
>   
>   void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
> @@ -1027,7 +1048,7 @@ void intel_vrr_transcoder_enable(const struct intel_crtc_state *crtc_state)
>   		return;
>   
>   	if (intel_vrr_always_use_vrr_tg(display))
> -		intel_vrr_tg_enable(crtc_state, false);
> +		intel_vrr_tg_enable(crtc_state);
>   }
>   
>   void intel_vrr_transcoder_disable(const struct intel_crtc_state *old_crtc_state)

Re: [PATCH v7 10/10] drm/i915/vrr: Enable cmrr

[Borah, Chaitanya Kumar]

On 7/28/2026 8:29 PM, Mitul Golani wrote:
> Enable CMRR during compute config and add related state
> checker for the same.
> 

stale commit message, there is no state checking any more.

Otherwise the patch looks good, I will wait for the remaining review 
comments to be resolved before RB'ing this one.

> --v2:
> - Everything else except enable compute to handle before this patch
> (Chaitanya)
> 
> --v3:
> - Remove redundant return from compute config
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_vrr.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 8d871aa58cab..c17df4675ec1 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -277,6 +277,8 @@ intel_vrr_cmrr_compute_config(struct intel_crtc_state *crtc_state)
>   	adjusted_mode->crtc_vtotal = div64_u64_rem(dividend,
>   						   crtc_state->vrr.cmrr.cmrr_n,
>   						   &crtc_state->vrr.cmrr.cmrr_m);
> +
> +	crtc_state->vrr.cmrr.enable = true;
>   }
>   
>   static