[PATCH 5.15.y] drm/amd/display: Skip inactive planes within ModeSupportAndSystemConfiguration

[PATCH 5.15.y] drm/amd/display: Skip inactive planes within ModeSupportAndSystemConfiguration

[jianqi.ren.cn]

From: Hersen Wu <hersenxs.wu@amd.com>

[ Upstream commit a54f7e866cc73a4cb71b8b24bb568ba35c8969df ]

[Why]
Coverity reports Memory - illegal accesses.

[How]
Skip inactive planes.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[get_pipe_idx() was introduced as a helper by
dda4fb85e433 ("drm/amd/display: DML changes for DCN32/321") in v6.0.
This patch backports it to make code clearer. And minor conflict is
resolved due to code context change.]
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
---
Verified the build test
---
 .../drm/amd/display/dc/dml/display_mode_vba.c | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/display_mode_vba.c b/drivers/gpu/drm/amd/display/dc/dml/display_mode_vba.c
index 0fad15020c74..2beca0b06925 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/display_mode_vba.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/display_mode_vba.c
@@ -867,11 +867,30 @@ static unsigned int CursorBppEnumToBits(enum cursor_bpp ebpp)
 	}
 }
 
+static unsigned int get_pipe_idx(struct display_mode_lib *mode_lib, unsigned int plane_idx)
+{
+	int pipe_idx = -1;
+	int i;
+
+	ASSERT(plane_idx < DC__NUM_DPP__MAX);
+
+	for (i = 0; i < DC__NUM_DPP__MAX ; i++) {
+		if (plane_idx == mode_lib->vba.pipe_plane[i]) {
+			pipe_idx = i;
+			break;
+		}
+	}
+	ASSERT(pipe_idx >= 0);
+
+	return pipe_idx;
+}
+
 void ModeSupportAndSystemConfiguration(struct display_mode_lib *mode_lib)
 {
 	soc_bounding_box_st *soc = &mode_lib->vba.soc;
 	unsigned int k;
 	unsigned int total_pipes = 0;
+	unsigned int pipe_idx = 0;
 
 	mode_lib->vba.VoltageLevel = mode_lib->vba.cache_pipes[0].clks_cfg.voltage;
 	mode_lib->vba.ReturnBW = mode_lib->vba.ReturnBWPerState[mode_lib->vba.VoltageLevel][mode_lib->vba.maxMpcComb];
@@ -892,6 +911,11 @@ void ModeSupportAndSystemConfiguration(struct display_mode_lib *mode_lib)
 
 	// Total Available Pipes Support Check
 	for (k = 0; k < mode_lib->vba.NumberOfActivePlanes; ++k) {
+		pipe_idx = get_pipe_idx(mode_lib, k);
+		if (pipe_idx == -1) {
+			ASSERT(0);
+			continue; // skip inactive planes
+		}
 		total_pipes += mode_lib->vba.DPPPerPlane[k];
 	}
 	ASSERT(total_pipes <= DC__NUM_DPP__MAX);
-- 
2.34.1

Re: [PATCH 5.15.y] drm/amd/display: Skip inactive planes within ModeSupportAndSystemConfiguration

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: a54f7e866cc73a4cb71b8b24bb568ba35c8969df

WARNING: Author mismatch between patch and upstream commit:
Backport author: <jianqi.ren.cn@windriver.com>
Commit author: Hersen Wu<hersenxs.wu@amd.com>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.13.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (different SHA1: 8406158a5464)
6.1.y | Present (different SHA1: 3300a039caf8)

Note: The patch differs from the upstream commit:
---
1:  a54f7e866cc73 < -:  ------------- drm/amd/display: Skip inactive planes within ModeSupportAndSystemConfiguration
-:  ------------- > 1:  5791f5818e634 drm/amd/display: Skip inactive planes within ModeSupportAndSystemConfiguration
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.15.y       |  Success    |  Success   |