[RFC 5/7] drm/i915/dp: Validate modes that can only be handled in a bigjoiner configuration

Maarten Lankhorst
2019-07-02T19:42:11Z

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
drivers/gpu/drm/i915/display/intel_dp.c | 234 +++++++++++++-----------
drivers/gpu/drm/i915/display/intel_dp.h | 4 -
2 files changed, 130 insertions(+), 108 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index b41ff88d3258..bf28970c01aa 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -248,7 +248,7 @@ intel_dp_max_data_rate(int max_link_clock, int max_lanes)
}

static int
-intel_dp_downstream_max_dotclock(struct intel_dp *intel_dp)
+intel_dp_downstream_max_dotclock(struct intel_dp *intel_dp, bool allow_bigjoiner)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
struct intel_encoder *encoder = &intel_dig_port->base;
@@ -258,6 +258,9 @@ intel_dp_downstream_max_dotclock(struct intel_dp *intel_dp)

int type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;

+ if (allow_bigjoiner && INTEL_GEN(dev_priv) >= 11)
+ max_dotclk *= 2;
+
if (type != DP_DS_PORT_TYPE_VGA)
return max_dotclk;

@@ -493,6 +496,103 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
return 0;
}

+static u16 intel_dp_dsc_get_output_bpp(int link_clock, u8 lane_count,
+ int mode_clock, int mode_hdisplay,
+ bool bigjoiner)
+{
+ u16 bits_per_pixel, max_bpp_small_joiner_ram;
+ int i;
+
+ /*
+ * Available Link Bandwidth(Kbits/sec) = (NumberOfLanes)*
+ * (LinkSymbolClock)* 8 * ((100-FECOverhead)/100)*(TimeSlotsPerMTP)
+ * FECOverhead = 2.4%, for SST -> TimeSlotsPerMTP is 1,
+ * for MST -> TimeSlotsPerMTP has to be calculated
+ */
+ bits_per_pixel = (link_clock * lane_count * 8 *
+ DP_DSC_FEC_OVERHEAD_FACTOR) /
+ mode_clock;
+
+ /* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
+ max_bpp_small_joiner_ram = DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER /
+ mode_hdisplay;
+
+ if (bigjoiner)
+ max_bpp_small_joiner_ram *= 2;
+
+ /*
+ * Greatest allowed DSC BPP = MIN (output BPP from avaialble Link BW
+ * check, output bpp from small joiner RAM check)
+ */
+ bits_per_pixel = min(bits_per_pixel, max_bpp_small_joiner_ram);
+
+ /* Error out if the max bpp is less than smallest allowed valid bpp */
+ if (bits_per_pixel < valid_dsc_bpp[0]) {
+ DRM_DEBUG_KMS("Unsupported BPP %d\n", bits_per_pixel);
+ return 0;
+ }
+
+ /* Find the nearest match in the array of known BPPs from VESA */
+ for (i = 0; i < ARRAY_SIZE(valid_dsc_bpp) - 1; i++) {
+ if (bits_per_pixel < valid_dsc_bpp[i + 1])
+ break;
+ }
+ bits_per_pixel = valid_dsc_bpp[i];
+
+ /*
+ * Compressed BPP in U6.4 format so multiply by 16, for Gen 11,
+ * fractional part is 0
+ */
+ return bits_per_pixel << 4;
+}
+
+static u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
+ int mode_clock, int mode_hdisplay,
+ bool bigjoiner)
+{
+ u8 min_slice_count, i;
+ int max_slice_width;
+
+ if (mode_clock <= DP_DSC_PEAK_PIXEL_RATE)
+ min_slice_count = DIV_ROUND_UP(mode_clock,
+ DP_DSC_MAX_ENC_THROUGHPUT_0);
+ else
+ min_slice_count = DIV_ROUND_UP(mode_clock,
+ DP_DSC_MAX_ENC_THROUGHPUT_1);
+
+ max_slice_width = drm_dp_dsc_sink_max_slice_width(intel_dp->dsc_dpcd);
+ if (max_slice_width < DP_DSC_MIN_SLICE_WIDTH_VALUE) {
+ DRM_DEBUG_KMS("Unsupported slice width %d by DP DSC Sink device\n",
+ max_slice_width);
+ return 0;
+ }
+ /* Also take into account max slice width */
+ min_slice_count = min_t(u8, min_slice_count,
+ DIV_ROUND_UP(mode_hdisplay,
+ max_slice_width));
+
+ /* Find the closest match to the valid slice count values */
+ for (i = 0; i < ARRAY_SIZE(valid_dsc_slicecount); i++) {
+ u8 test_slice_count = bigjoiner ?
+ 2 * valid_dsc_slicecount[i] :
+ valid_dsc_slicecount[i];
+
+ if (test_slice_count >
+ drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd, false))
+ break;
+
+ /* big joiner needs small joiner to be enabled */
+ if (bigjoiner && test_slice_count < 4)
+ continue;
+
+ if (min_slice_count <= test_slice_count)
+ return test_slice_count;
+ }
+
+ DRM_DEBUG_KMS("Unsupported Slice Count %d\n", min_slice_count);
+ return 0;
+}
+
static enum drm_mode_status
intel_dp_mode_valid(struct drm_connector *connector,
struct drm_display_mode *mode)
@@ -506,12 +606,15 @@ intel_dp_mode_valid(struct drm_connector *connector,
int max_dotclk;
u16 dsc_max_output_bpp = 0;
u8 dsc_slice_count = 0;
- bool dsc;
+ bool dsc = false, bigjoiner = false;

if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
return MODE_NO_DBLESCAN;

- max_dotclk = intel_dp_downstream_max_dotclock(intel_dp);
+ if (mode->flags & DRM_MODE_FLAG_DBLCLK)
+ return MODE_H_ILLEGAL;
+
+ max_dotclk = intel_dp_downstream_max_dotclock(intel_dp, false);

if (intel_dp_is_edp(intel_dp) && fixed_mode) {
if (mode->hdisplay > fixed_mode->hdisplay)
@@ -523,6 +626,18 @@ intel_dp_mode_valid(struct drm_connector *connector,
target_clock = fixed_mode->clock;
}

+ if (mode->clock < 10000)
+ return MODE_CLOCK_LOW;
+
+ if (target_clock > max_dotclk) {
+ max_dotclk = intel_dp_downstream_max_dotclock(intel_dp, true);
+
+ if (target_clock > max_dotclk)
+ return MODE_CLOCK_HIGH;
+
+ bigjoiner = true;
+ }
+
max_link_clock = intel_dp_max_link_rate(intel_dp);
max_lanes = intel_dp_max_lane_count(intel_dp);

@@ -546,28 +661,24 @@ intel_dp_mode_valid(struct drm_connector *connector,
intel_dp_dsc_get_output_bpp(max_link_clock,
max_lanes,
target_clock,
- mode->hdisplay) >> 4;
+ mode->hdisplay,
+ bigjoiner) >> 4;
dsc_slice_count =
intel_dp_dsc_get_slice_count(intel_dp,
target_clock,
- mode->hdisplay);
+ mode->hdisplay,
+ bigjoiner);
}
- }
-
- dsc = dsc_max_output_bpp && dsc_slice_count;

- /* Gen11 has big joiner for handling this */
- if (dsc && dsc_slice_count >= 2 && INTEL_GEN(dev_priv) >= 11)
- max_dotclk *= 2;
+ dsc = dsc_max_output_bpp && dsc_slice_count;
+ }

- if ((mode_rate > max_rate && !dsc) || target_clock > max_dotclk)
+ /* big joiner configuration needs DSC */
+ if (bigjoiner && !dsc)
return MODE_CLOCK_HIGH;

- if (mode->clock < 10000)
- return MODE_CLOCK_LOW;
-
- if (mode->flags & DRM_MODE_FLAG_DBLCLK)
- return MODE_H_ILLEGAL;
+ if (mode_rate > max_rate && !dsc)
+ return MODE_CLOCK_HIGH;

return MODE_OK;
}
@@ -1950,11 +2061,11 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
intel_dp_dsc_get_output_bpp(pipe_config->port_clock,
pipe_config->lane_count,
adjusted_mode->crtc_clock,
- adjusted_mode->crtc_hdisplay);
+ adjusted_mode->crtc_hdisplay, false);
dsc_dp_slice_count =
intel_dp_dsc_get_slice_count(intel_dp,
adjusted_mode->crtc_clock,
- adjusted_mode->crtc_hdisplay);
+ adjusted_mode->crtc_hdisplay, false);
if (!dsc_max_output_bpp || !dsc_dp_slice_count) {
DRM_DEBUG_KMS("Compressed BPP/Slice Count not supported\n");
return -EINVAL;
@@ -4325,91 +4436,6 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
DP_DPRX_ESI_LEN;
}

-u16 intel_dp_dsc_get_output_bpp(int link_clock, u8 lane_count,
- int mode_clock, int mode_hdisplay)
-{
- u16 bits_per_pixel, max_bpp_small_joiner_ram;
- int i;
-
- /*
- * Available Link Bandwidth(Kbits/sec) = (NumberOfLanes)*
- * (LinkSymbolClock)* 8 * ((100-FECOverhead)/100)*(TimeSlotsPerMTP)
- * FECOverhead = 2.4%, for SST -> TimeSlotsPerMTP is 1,
- * for MST -> TimeSlotsPerMTP has to be calculated
- */
- bits_per_pixel = (link_clock * lane_count * 8 *
- DP_DSC_FEC_OVERHEAD_FACTOR) /
- mode_clock;
-
- /* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
- max_bpp_small_joiner_ram = DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER /
- mode_hdisplay;
-
- /*
- * Greatest allowed DSC BPP = MIN (output BPP from avaialble Link BW
- * check, output bpp from small joiner RAM check)
- */
- bits_per_pixel = min(bits_per_pixel, max_bpp_small_joiner_ram);
-
- /* Error out if the max bpp is less than smallest allowed valid bpp */
- if (bits_per_pixel < valid_dsc_bpp[0]) {
- DRM_DEBUG_KMS("Unsupported BPP %d\n", bits_per_pixel);
- return 0;
- }
-
- /* Find the nearest match in the array of known BPPs from VESA */
- for (i = 0; i < ARRAY_SIZE(valid_dsc_bpp) - 1; i++) {
- if (bits_per_pixel < valid_dsc_bpp[i + 1])
- break;
- }
- bits_per_pixel = valid_dsc_bpp[i];
-
- /*
- * Compressed BPP in U6.4 format so multiply by 16, for Gen 11,
- * fractional part is 0
- */
- return bits_per_pixel << 4;
-}
-
-u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
- int mode_clock,
- int mode_hdisplay)
-{
- u8 min_slice_count, i;
- int max_slice_width;
-
- if (mode_clock <= DP_DSC_PEAK_PIXEL_RATE)
- min_slice_count = DIV_ROUND_UP(mode_clock,
- DP_DSC_MAX_ENC_THROUGHPUT_0);
- else
- min_slice_count = DIV_ROUND_UP(mode_clock,
- DP_DSC_MAX_ENC_THROUGHPUT_1);
-
- max_slice_width = drm_dp_dsc_sink_max_slice_width(intel_dp->dsc_dpcd);
- if (max_slice_width < DP_DSC_MIN_SLICE_WIDTH_VALUE) {
- DRM_DEBUG_KMS("Unsupported slice width %d by DP DSC Sink device\n",
- max_slice_width);
- return 0;
- }
- /* Also take into account max slice width */
- min_slice_count = min_t(u8, min_slice_count,
- DIV_ROUND_UP(mode_hdisplay,
- max_slice_width));
-
- /* Find the closest match to the valid slice count values */
- for (i = 0; i < ARRAY_SIZE(valid_dsc_slicecount); i++) {
- if (valid_dsc_slicecount[i] >
- drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
- false))
- break;
- if (min_slice_count <= valid_dsc_slicecount[i])
- return valid_dsc_slicecount[i];
- }
-
- DRM_DEBUG_KMS("Unsupported Slice Count %d\n", min_slice_count);
- return 0;
-}
-
static void
intel_pixel_encoding_setup_vsc(struct intel_dp *intel_dp,
const struct intel_crtc_state *crtc_state)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 657bbb1f5ed0..b11ca45272ed 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -102,10 +102,6 @@ bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp);
bool intel_dp_source_supports_hbr3(struct intel_dp *intel_dp);
bool
intel_dp_get_link_status(struct intel_dp *intel_dp, u8 *link_status);
-u16 intel_dp_dsc_get_output_bpp(int link_clock, u8 lane_count,
- int mode_clock, int mode_hdisplay);
-u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp, int mode_clock,
- int mode_hdisplay);

bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp);
--
2.20.1