[PATCH 6.18 127/314] drm/i915/dp: Fail state computation for invalid DSC source input BPP values

Sasha Levin
2026-03-10T11:26:41Z

From: Imre Deak <imre.deak@intel.com>

[ Upstream commit 338465490cf7bd4a700ecd33e4855fee4622fa5f ]

There is no reason to accept an invalid minimum/maximum DSC source input
BPP value (i.e a minimum DSC input BPP value above the maximum pipe BPP
or a maximum DSC input BPP value below the minimum pipe BPP value), fail
the state computation in these cases.

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20251215192357.172201-17-imre.deak@intel.com
Stable-dep-of: fe26ae6ac8b8 ("drm/i915/dp: Fix pipe BPP clamping due to HDR")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/i915/display/intel_dp.c | 28 ++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 2eab591a8ef56..057b366c5ae29 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2523,16 +2523,30 @@ intel_dp_compute_config_link_bpp_limits(struct intel_dp *intel_dp,
return true;
}

-static void
-intel_dp_dsc_compute_pipe_bpp_limits(struct intel_dp *intel_dp,
+static bool
+intel_dp_dsc_compute_pipe_bpp_limits(struct intel_connector *connector,
struct link_config_limits *limits)
{
- struct intel_display *display = to_intel_display(intel_dp);
+ struct intel_display *display = to_intel_display(connector);
+ const struct link_config_limits orig_limits = *limits;
int dsc_min_bpc = intel_dp_dsc_min_src_input_bpc();
int dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(display);

- limits->pipe.max_bpp = clamp(limits->pipe.max_bpp, dsc_min_bpc * 3, dsc_max_bpc * 3);
- limits->pipe.min_bpp = clamp(limits->pipe.min_bpp, dsc_min_bpc * 3, dsc_max_bpc * 3);
+ limits->pipe.min_bpp = max(limits->pipe.min_bpp, dsc_min_bpc * 3);
+ limits->pipe.max_bpp = min(limits->pipe.max_bpp, dsc_max_bpc * 3);
+
+ if (limits->pipe.min_bpp <= 0 ||
+ limits->pipe.min_bpp > limits->pipe.max_bpp) {
+ drm_dbg_kms(display->drm,
+ "[CONNECTOR:%d:%s] Invalid DSC src/sink input BPP (src:%d-%d pipe:%d-%d)\n",
+ connector->base.base.id, connector->base.name,
+ dsc_min_bpc * 3, dsc_max_bpc * 3,
+ orig_limits.pipe.min_bpp, orig_limits.pipe.max_bpp);
+
+ return false;
+ }
+
+ return true;
}

bool
@@ -2572,8 +2586,8 @@ intel_dp_compute_config_limits(struct intel_dp *intel_dp,
respect_downstream_limits);
}

- if (dsc)
- intel_dp_dsc_compute_pipe_bpp_limits(intel_dp, limits);
+ if (dsc && !intel_dp_dsc_compute_pipe_bpp_limits(connector, limits))
+ return false;

if (is_mst || intel_dp->use_max_params) {
/*
--
2.51.0