[PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Kees Cook]

The link_status array was not large enough to read the Adjust Request
Post Cursor2 register. Adjust the size to include it. Found with a
-Warray-bounds build:

drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
   59 |         return link_status[r - DP_LANE0_1_STATUS];
      |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
  147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
      |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v2: Fix missed array size change in intel_dp_check_mst_status()
---
 drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
 include/drm/drm_dp_helper.h             | 10 +++++++++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5a8206298691..97367afc7243 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3647,17 +3647,17 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
 
 	for (;;) {
 		/*
-		 * The +2 is because DP_DPRX_ESI_LEN is 14, but we then
+		 * The +10 is because while DP_DPRX_ESI_LEN is 14, we then
 		 * pass in "esi+10" to drm_dp_channel_eq_ok(), which
-		 * takes a 6-byte array. So we actually need 16 bytes
-		 * here.
+		 * takes a DP_LINK_STATUS_SIZE array. So we actually need
+		 * 10 bytes more than DP_LINK_STATUS_SIZE.
 		 *
 		 * Somebody who knows what the limits actually are
 		 * should check this, but for now this is at least
 		 * harmless and avoids a valid compiler warning about
 		 * using more of the array than we have allocated.
 		 */
-		u8 esi[DP_DPRX_ESI_LEN+2] = {};
+		u8 esi[DP_LINK_STATUS_SIZE + 10] = {};
 		bool handled;
 		int retry;
 
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 472dac376284..277643d2fe2c 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1517,7 +1517,15 @@ enum drm_dp_phy {
 #define DP_MST_LOGICAL_PORT_0 8
 
 #define DP_LINK_CONSTANT_N_VALUE 0x8000
-#define DP_LINK_STATUS_SIZE	   6
+/*
+ * DPCD registers in link_status:
+ * Link Status:		0x202 through 0x204
+ * Sink Status:		0x205
+ * Adjust Request:	0x206 through 0x207
+ * Training Score:	0x208 through 0x20b
+ * AR Post Cursor2:	0x20c
+ */
+#define DP_LINK_STATUS_SIZE	   11
 bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 			  int lane_count);
 bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
-- 
2.30.2

[PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Kees Cook]

The link_status array was not large enough to read the Adjust Request
Post Cursor2 register. Adjust the size to include it. Found with a
-Warray-bounds build:

drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
   59 |         return link_status[r - DP_LANE0_1_STATUS];
      |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
  147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
      |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v2: Fix missed array size change in intel_dp_check_mst_status()
---
 drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
 include/drm/drm_dp_helper.h             | 10 +++++++++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5a8206298691..97367afc7243 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3647,17 +3647,17 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
 
 	for (;;) {
 		/*
-		 * The +2 is because DP_DPRX_ESI_LEN is 14, but we then
+		 * The +10 is because while DP_DPRX_ESI_LEN is 14, we then
 		 * pass in "esi+10" to drm_dp_channel_eq_ok(), which
-		 * takes a 6-byte array. So we actually need 16 bytes
-		 * here.
+		 * takes a DP_LINK_STATUS_SIZE array. So we actually need
+		 * 10 bytes more than DP_LINK_STATUS_SIZE.
 		 *
 		 * Somebody who knows what the limits actually are
 		 * should check this, but for now this is at least
 		 * harmless and avoids a valid compiler warning about
 		 * using more of the array than we have allocated.
 		 */
-		u8 esi[DP_DPRX_ESI_LEN+2] = {};
+		u8 esi[DP_LINK_STATUS_SIZE + 10] = {};
 		bool handled;
 		int retry;
 
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 472dac376284..277643d2fe2c 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1517,7 +1517,15 @@ enum drm_dp_phy {
 #define DP_MST_LOGICAL_PORT_0 8
 
 #define DP_LINK_CONSTANT_N_VALUE 0x8000
-#define DP_LINK_STATUS_SIZE	   6
+/*
+ * DPCD registers in link_status:
+ * Link Status:		0x202 through 0x204
+ * Sink Status:		0x205
+ * Adjust Request:	0x206 through 0x207
+ * Training Score:	0x208 through 0x20b
+ * AR Post Cursor2:	0x20c
+ */
+#define DP_LINK_STATUS_SIZE	   11
 bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 			  int lane_count);
 bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
-- 
2.30.2

[Intel-gfx] [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Kees Cook]

The link_status array was not large enough to read the Adjust Request
Post Cursor2 register. Adjust the size to include it. Found with a
-Warray-bounds build:

drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
   59 |         return link_status[r - DP_LANE0_1_STATUS];
      |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
  147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
      |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v2: Fix missed array size change in intel_dp_check_mst_status()
---
 drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
 include/drm/drm_dp_helper.h             | 10 +++++++++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5a8206298691..97367afc7243 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3647,17 +3647,17 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
 
 	for (;;) {
 		/*
-		 * The +2 is because DP_DPRX_ESI_LEN is 14, but we then
+		 * The +10 is because while DP_DPRX_ESI_LEN is 14, we then
 		 * pass in "esi+10" to drm_dp_channel_eq_ok(), which
-		 * takes a 6-byte array. So we actually need 16 bytes
-		 * here.
+		 * takes a DP_LINK_STATUS_SIZE array. So we actually need
+		 * 10 bytes more than DP_LINK_STATUS_SIZE.
 		 *
 		 * Somebody who knows what the limits actually are
 		 * should check this, but for now this is at least
 		 * harmless and avoids a valid compiler warning about
 		 * using more of the array than we have allocated.
 		 */
-		u8 esi[DP_DPRX_ESI_LEN+2] = {};
+		u8 esi[DP_LINK_STATUS_SIZE + 10] = {};
 		bool handled;
 		int retry;
 
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 472dac376284..277643d2fe2c 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1517,7 +1517,15 @@ enum drm_dp_phy {
 #define DP_MST_LOGICAL_PORT_0 8
 
 #define DP_LINK_CONSTANT_N_VALUE 0x8000
-#define DP_LINK_STATUS_SIZE	   6
+/*
+ * DPCD registers in link_status:
+ * Link Status:		0x202 through 0x204
+ * Sink Status:		0x205
+ * Adjust Request:	0x206 through 0x207
+ * Training Score:	0x208 through 0x20b
+ * AR Post Cursor2:	0x20c
+ */
+#define DP_LINK_STATUS_SIZE	   11
 bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 			  int lane_count);
 bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
-- 
2.30.2

[Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/dp: Actually read Adjust Request Post Cursor2 register

[Patchwork]

== Series Details ==

Series: drm/dp: Actually read Adjust Request Post Cursor2 register
URL   : https://patchwork.freedesktop.org/series/97533/
State : warning

== Summary ==

$ dim checkpatch origin/drm-tip
1de58e82192d drm/dp: Actually read Adjust Request Post Cursor2 register
-:15: WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#15: 
  147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],

total: 0 errors, 1 warnings, 0 checks, 37 lines checked

[Intel-gfx] ✗ Fi.CI.SPARSE: warning for drm/dp: Actually read Adjust Request Post Cursor2 register

[Patchwork]

== Series Details ==

Series: drm/dp: Actually read Adjust Request Post Cursor2 register
URL   : https://patchwork.freedesktop.org/series/97533/
State : warning

== Summary ==

$ dim sparse --fast origin/drm-tip
Sparse version: v0.6.2
Fast mode used, each commit won't be checked separately.

[Intel-gfx] ✓ Fi.CI.BAT: success for drm/dp: Actually read Adjust Request Post Cursor2 register

[Patchwork]

[-- Attachment #1: Type: text/plain, Size: 5459 bytes --]

== Series Details ==

Series: drm/dp: Actually read Adjust Request Post Cursor2 register
URL   : https://patchwork.freedesktop.org/series/97533/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_10959 -> Patchwork_21740
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/index.html

Participating hosts (40 -> 33)
------------------------------

  Missing    (7): bat-dg1-6 bat-dg1-5 fi-bsw-cyan bat-adlp-4 fi-pnv-d510 bat-jsl-2 bat-jsl-1 

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

  Here are the changes found in Patchwork_21740 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@amdgpu/amd_basic@cs-gfx:
    - fi-rkl-guc:         NOTRUN -> [SKIP][1] ([fdo#109315]) +17 similar issues
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-rkl-guc/igt@amdgpu/amd_basic@cs-gfx.html

  * igt@amdgpu/amd_basic@query-info:
    - fi-bsw-kefka:       NOTRUN -> [SKIP][2] ([fdo#109271]) +35 similar issues
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-bsw-kefka/igt@amdgpu/amd_basic@query-info.html

  * igt@gem_exec_suspend@basic-s3:
    - fi-bdw-5557u:       [PASS][3] -> [INCOMPLETE][4] ([i915#146])
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-bdw-5557u/igt@gem_exec_suspend@basic-s3.html
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-bdw-5557u/igt@gem_exec_suspend@basic-s3.html

  * igt@kms_chamelium@hdmi-edid-read:
    - fi-bsw-kefka:       NOTRUN -> [SKIP][5] ([fdo#109271] / [fdo#111827]) +8 similar issues
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-bsw-kefka/igt@kms_chamelium@hdmi-edid-read.html

  * igt@kms_frontbuffer_tracking@basic:
    - fi-cfl-8109u:       [PASS][6] -> [DMESG-FAIL][7] ([i915#295])
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-cfl-8109u/igt@kms_frontbuffer_tracking@basic.html
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-cfl-8109u/igt@kms_frontbuffer_tracking@basic.html

  * igt@kms_pipe_crc_basic@compare-crc-sanitycheck-pipe-b:
    - fi-cfl-8109u:       [PASS][8] -> [DMESG-WARN][9] ([i915#295]) +10 similar issues
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-cfl-8109u/igt@kms_pipe_crc_basic@compare-crc-sanitycheck-pipe-b.html
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-cfl-8109u/igt@kms_pipe_crc_basic@compare-crc-sanitycheck-pipe-b.html

  * igt@kms_psr@primary_page_flip:
    - fi-skl-6600u:       [PASS][10] -> [FAIL][11] ([i915#4547])
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-skl-6600u/igt@kms_psr@primary_page_flip.html
   [11]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-skl-6600u/igt@kms_psr@primary_page_flip.html

  * igt@runner@aborted:
    - fi-skl-6600u:       NOTRUN -> [FAIL][12] ([i915#3363] / [i915#4312])
   [12]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-skl-6600u/igt@runner@aborted.html

  
#### Possible fixes ####

  * igt@gem_exec_suspend@basic-s0:
    - fi-bsw-kefka:       [INCOMPLETE][13] ([i915#2539]) -> [PASS][14]
   [13]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-bsw-kefka/igt@gem_exec_suspend@basic-s0.html
   [14]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-bsw-kefka/igt@gem_exec_suspend@basic-s0.html

  * igt@i915_selftest@live@gt_engines:
    - fi-rkl-guc:         [INCOMPLETE][15] ([i915#4432]) -> [PASS][16]
   [15]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-rkl-guc/igt@i915_selftest@live@gt_engines.html
   [16]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-rkl-guc/igt@i915_selftest@live@gt_engines.html

  * igt@kms_frontbuffer_tracking@basic:
    - fi-cml-u2:          [DMESG-WARN][17] ([i915#4269]) -> [PASS][18]
   [17]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/fi-cml-u2/igt@kms_frontbuffer_tracking@basic.html
   [18]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/fi-cml-u2/igt@kms_frontbuffer_tracking@basic.html

  
  [fdo#109271]: https://bugs.freedesktop.org/show_bug.cgi?id=109271
  [fdo#109315]: https://bugs.freedesktop.org/show_bug.cgi?id=109315
  [fdo#111827]: https://bugs.freedesktop.org/show_bug.cgi?id=111827
  [i915#146]: https://gitlab.freedesktop.org/drm/intel/issues/146
  [i915#2539]: https://gitlab.freedesktop.org/drm/intel/issues/2539
  [i915#295]: https://gitlab.freedesktop.org/drm/intel/issues/295
  [i915#3363]: https://gitlab.freedesktop.org/drm/intel/issues/3363
  [i915#4269]: https://gitlab.freedesktop.org/drm/intel/issues/4269
  [i915#4312]: https://gitlab.freedesktop.org/drm/intel/issues/4312
  [i915#4432]: https://gitlab.freedesktop.org/drm/intel/issues/4432
  [i915#4547]: https://gitlab.freedesktop.org/drm/intel/issues/4547


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

  * Linux: CI_DRM_10959 -> Patchwork_21740

  CI-20190529: 20190529
  CI_DRM_10959: f4fd510ca94904204dd82f90459283531d63cf19 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_6299: 0933b7ccdb2bb054b6a8154171e35315d84299b7 @ https://gitlab.freedesktop.org/drm/igt-gpu-tools.git
  Patchwork_21740: 1de58e82192dd5799f5708b337669e300e146fb4 @ git://anongit.freedesktop.org/gfx-ci/linux


== Linux commits ==

1de58e82192d drm/dp: Actually read Adjust Request Post Cursor2 register

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/index.html

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Re: [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Thierry Reding]

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On Fri, Dec 03, 2021 at 01:25:17AM -0800, Kees Cook wrote:
> The link_status array was not large enough to read the Adjust Request
> Post Cursor2 register. Adjust the size to include it. Found with a
> -Warray-bounds build:
> 
> drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
> drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
>    59 |         return link_status[r - DP_LANE0_1_STATUS];
>       |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
>   147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
>       |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> v2: Fix missed array size change in intel_dp_check_mst_status()
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
>  include/drm/drm_dp_helper.h             | 10 +++++++++-
>  2 files changed, 13 insertions(+), 5 deletions(-)

This sounds very familiar and I vaguely recall typing up a patch like
that a long time ago. But I obviously failed because that never seems
to have made it upstream.

Or perhaps I'm misremembering and was thinking about this instead:

	https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/338590/

Bonus points for adding that comment with background information on why
we need this.

Reviewed-by: Thierry Reding <treding@nvidia.com>

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Re: [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Thierry Reding]

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On Fri, Dec 03, 2021 at 01:25:17AM -0800, Kees Cook wrote:
> The link_status array was not large enough to read the Adjust Request
> Post Cursor2 register. Adjust the size to include it. Found with a
> -Warray-bounds build:
> 
> drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
> drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
>    59 |         return link_status[r - DP_LANE0_1_STATUS];
>       |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
>   147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
>       |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> v2: Fix missed array size change in intel_dp_check_mst_status()
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
>  include/drm/drm_dp_helper.h             | 10 +++++++++-
>  2 files changed, 13 insertions(+), 5 deletions(-)

This sounds very familiar and I vaguely recall typing up a patch like
that a long time ago. But I obviously failed because that never seems
to have made it upstream.

Or perhaps I'm misremembering and was thinking about this instead:

	https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/338590/

Bonus points for adding that comment with background information on why
we need this.

Reviewed-by: Thierry Reding <treding@nvidia.com>

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Re: [Intel-gfx] [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 1733 bytes --]

On Fri, Dec 03, 2021 at 01:25:17AM -0800, Kees Cook wrote:
> The link_status array was not large enough to read the Adjust Request
> Post Cursor2 register. Adjust the size to include it. Found with a
> -Warray-bounds build:
> 
> drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
> drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
>    59 |         return link_status[r - DP_LANE0_1_STATUS];
>       |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
>   147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
>       |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> v2: Fix missed array size change in intel_dp_check_mst_status()
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
>  include/drm/drm_dp_helper.h             | 10 +++++++++-
>  2 files changed, 13 insertions(+), 5 deletions(-)

This sounds very familiar and I vaguely recall typing up a patch like
that a long time ago. But I obviously failed because that never seems
to have made it upstream.

Or perhaps I'm misremembering and was thinking about this instead:

	https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/338590/

Bonus points for adding that comment with background information on why
we need this.

Reviewed-by: Thierry Reding <treding@nvidia.com>

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[Intel-gfx] ✗ Fi.CI.IGT: failure for drm/dp: Actually read Adjust Request Post Cursor2 register

[Patchwork]

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== Series Details ==

Series: drm/dp: Actually read Adjust Request Post Cursor2 register
URL   : https://patchwork.freedesktop.org/series/97533/
State : failure

== Summary ==

CI Bug Log - changes from CI_DRM_10959_full -> Patchwork_21740_full
====================================================

Summary
-------

  **FAILURE**

  Serious unknown changes coming with Patchwork_21740_full absolutely need to be
  verified manually.
  
  If you think the reported changes have nothing to do with the changes
  introduced in Patchwork_21740_full, please notify your bug team to allow them
  to document this new failure mode, which will reduce false positives in CI.

  

Participating hosts (10 -> 10)
------------------------------

  No changes in participating hosts

Possible new issues
-------------------

  Here are the unknown changes that may have been introduced in Patchwork_21740_full:

### IGT changes ###

#### Possible regressions ####

  * igt@i915_suspend@sysfs-reader:
    - shard-kbl:          NOTRUN -> [INCOMPLETE][1]
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl4/igt@i915_suspend@sysfs-reader.html

  * igt@kms_atomic_transition@modeset-transition-fencing@1x-outputs:
    - shard-tglb:         [PASS][2] -> [INCOMPLETE][3]
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-tglb3/igt@kms_atomic_transition@modeset-transition-fencing@1x-outputs.html
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb8/igt@kms_atomic_transition@modeset-transition-fencing@1x-outputs.html

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

  Here are the changes found in Patchwork_21740_full that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@gem_eio@in-flight-contexts-immediate:
    - shard-iclb:         [PASS][4] -> [TIMEOUT][5] ([i915#3070])
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-iclb2/igt@gem_eio@in-flight-contexts-immediate.html
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb8/igt@gem_eio@in-flight-contexts-immediate.html

  * igt@gem_eio@unwedge-stress:
    - shard-tglb:         [PASS][6] -> [TIMEOUT][7] ([i915#3063] / [i915#3648])
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-tglb8/igt@gem_eio@unwedge-stress.html
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb6/igt@gem_eio@unwedge-stress.html

  * igt@gem_exec_capture@pi@bcs0:
    - shard-skl:          NOTRUN -> [INCOMPLETE][8] ([i915#4547])
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl8/igt@gem_exec_capture@pi@bcs0.html

  * igt@gem_exec_fair@basic-none@rcs0:
    - shard-glk:          [PASS][9] -> [FAIL][10] ([i915#2842])
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-glk5/igt@gem_exec_fair@basic-none@rcs0.html
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-glk9/igt@gem_exec_fair@basic-none@rcs0.html

  * igt@gem_exec_fair@basic-pace@vcs1:
    - shard-iclb:         NOTRUN -> [FAIL][11] ([i915#2842]) +1 similar issue
   [11]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb1/igt@gem_exec_fair@basic-pace@vcs1.html
    - shard-kbl:          [PASS][12] -> [FAIL][13] ([i915#2842])
   [12]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl6/igt@gem_exec_fair@basic-pace@vcs1.html
   [13]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl1/igt@gem_exec_fair@basic-pace@vcs1.html

  * igt@gem_exec_params@secure-non-master:
    - shard-tglb:         NOTRUN -> [SKIP][14] ([fdo#112283])
   [14]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb2/igt@gem_exec_params@secure-non-master.html

  * igt@gem_huc_copy@huc-copy:
    - shard-tglb:         [PASS][15] -> [SKIP][16] ([i915#2190])
   [15]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-tglb5/igt@gem_huc_copy@huc-copy.html
   [16]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb6/igt@gem_huc_copy@huc-copy.html
    - shard-skl:          NOTRUN -> [SKIP][17] ([fdo#109271] / [i915#2190])
   [17]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl1/igt@gem_huc_copy@huc-copy.html

  * igt@gem_lmem_swapping@random:
    - shard-kbl:          NOTRUN -> [SKIP][18] ([fdo#109271] / [i915#4613]) +1 similar issue
   [18]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@gem_lmem_swapping@random.html

  * igt@gem_lmem_swapping@verify-random:
    - shard-skl:          NOTRUN -> [SKIP][19] ([fdo#109271] / [i915#4613]) +2 similar issues
   [19]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl9/igt@gem_lmem_swapping@verify-random.html

  * igt@gem_pwrite@basic-exhaustion:
    - shard-apl:          NOTRUN -> [WARN][20] ([i915#2658])
   [20]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@gem_pwrite@basic-exhaustion.html

  * igt@gem_softpin@noreloc-s3:
    - shard-skl:          [PASS][21] -> [INCOMPLETE][22] ([i915#198])
   [21]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-skl9/igt@gem_softpin@noreloc-s3.html
   [22]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl7/igt@gem_softpin@noreloc-s3.html

  * igt@gem_userptr_blits@input-checking:
    - shard-iclb:         NOTRUN -> [DMESG-WARN][23] ([i915#3002])
   [23]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb8/igt@gem_userptr_blits@input-checking.html

  * igt@kms_async_flips@crc:
    - shard-skl:          NOTRUN -> [FAIL][24] ([i915#4272])
   [24]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl1/igt@kms_async_flips@crc.html

  * igt@kms_big_fb@x-tiled-max-hw-stride-32bpp-rotate-180-async-flip:
    - shard-skl:          NOTRUN -> [FAIL][25] ([i915#3743])
   [25]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl3/igt@kms_big_fb@x-tiled-max-hw-stride-32bpp-rotate-180-async-flip.html

  * igt@kms_big_fb@y-tiled-max-hw-stride-64bpp-rotate-0-hflip:
    - shard-kbl:          NOTRUN -> [SKIP][26] ([fdo#109271] / [i915#3777]) +1 similar issue
   [26]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl4/igt@kms_big_fb@y-tiled-max-hw-stride-64bpp-rotate-0-hflip.html

  * igt@kms_big_fb@y-tiled-max-hw-stride-64bpp-rotate-180-hflip:
    - shard-skl:          NOTRUN -> [SKIP][27] ([fdo#109271] / [i915#3777])
   [27]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl10/igt@kms_big_fb@y-tiled-max-hw-stride-64bpp-rotate-180-hflip.html

  * igt@kms_ccs@pipe-a-ccs-on-another-bo-y_tiled_gen12_mc_ccs:
    - shard-apl:          NOTRUN -> [SKIP][28] ([fdo#109271] / [i915#3886])
   [28]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@kms_ccs@pipe-a-ccs-on-another-bo-y_tiled_gen12_mc_ccs.html

  * igt@kms_ccs@pipe-a-missing-ccs-buffer-y_tiled_ccs:
    - shard-tglb:         NOTRUN -> [SKIP][29] ([i915#3689]) +1 similar issue
   [29]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb3/igt@kms_ccs@pipe-a-missing-ccs-buffer-y_tiled_ccs.html

  * igt@kms_ccs@pipe-a-missing-ccs-buffer-y_tiled_gen12_mc_ccs:
    - shard-kbl:          NOTRUN -> [SKIP][30] ([fdo#109271] / [i915#3886]) +6 similar issues
   [30]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl2/igt@kms_ccs@pipe-a-missing-ccs-buffer-y_tiled_gen12_mc_ccs.html

  * igt@kms_ccs@pipe-b-crc-primary-basic-y_tiled_gen12_mc_ccs:
    - shard-skl:          NOTRUN -> [SKIP][31] ([fdo#109271] / [i915#3886]) +6 similar issues
   [31]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl1/igt@kms_ccs@pipe-b-crc-primary-basic-y_tiled_gen12_mc_ccs.html

  * igt@kms_ccs@pipe-c-bad-pixel-format-yf_tiled_ccs:
    - shard-apl:          NOTRUN -> [SKIP][32] ([fdo#109271]) +29 similar issues
   [32]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@kms_ccs@pipe-c-bad-pixel-format-yf_tiled_ccs.html

  * igt@kms_chamelium@dp-edid-change-during-suspend:
    - shard-glk:          NOTRUN -> [SKIP][33] ([fdo#109271] / [fdo#111827])
   [33]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-glk3/igt@kms_chamelium@dp-edid-change-during-suspend.html

  * igt@kms_chamelium@hdmi-mode-timings:
    - shard-kbl:          NOTRUN -> [SKIP][34] ([fdo#109271] / [fdo#111827]) +8 similar issues
   [34]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@kms_chamelium@hdmi-mode-timings.html

  * igt@kms_chamelium@vga-hpd-after-suspend:
    - shard-skl:          NOTRUN -> [SKIP][35] ([fdo#109271] / [fdo#111827]) +16 similar issues
   [35]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl10/igt@kms_chamelium@vga-hpd-after-suspend.html

  * igt@kms_color_chamelium@pipe-a-ctm-0-5:
    - shard-iclb:         NOTRUN -> [SKIP][36] ([fdo#109284] / [fdo#111827]) +1 similar issue
   [36]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb8/igt@kms_color_chamelium@pipe-a-ctm-0-5.html

  * igt@kms_color_chamelium@pipe-b-gamma:
    - shard-tglb:         NOTRUN -> [SKIP][37] ([fdo#109284] / [fdo#111827]) +1 similar issue
   [37]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb2/igt@kms_color_chamelium@pipe-b-gamma.html

  * igt@kms_color_chamelium@pipe-c-ctm-max:
    - shard-apl:          NOTRUN -> [SKIP][38] ([fdo#109271] / [fdo#111827]) +1 similar issue
   [38]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@kms_color_chamelium@pipe-c-ctm-max.html

  * igt@kms_content_protection@dp-mst-lic-type-1:
    - shard-tglb:         NOTRUN -> [SKIP][39] ([i915#3116])
   [39]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb2/igt@kms_content_protection@dp-mst-lic-type-1.html

  * igt@kms_content_protection@legacy:
    - shard-apl:          NOTRUN -> [TIMEOUT][40] ([i915#1319])
   [40]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@kms_content_protection@legacy.html

  * igt@kms_content_protection@srm:
    - shard-kbl:          NOTRUN -> [TIMEOUT][41] ([i915#1319])
   [41]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl4/igt@kms_content_protection@srm.html

  * igt@kms_cursor_crc@pipe-d-cursor-256x256-rapid-movement:
    - shard-iclb:         NOTRUN -> [SKIP][42] ([fdo#109278]) +2 similar issues
   [42]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb4/igt@kms_cursor_crc@pipe-d-cursor-256x256-rapid-movement.html

  * igt@kms_flip@flip-vs-expired-vblank-interruptible@b-hdmi-a1:
    - shard-glk:          [PASS][43] -> [FAIL][44] ([i915#79])
   [43]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-glk7/igt@kms_flip@flip-vs-expired-vblank-interruptible@b-hdmi-a1.html
   [44]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-glk4/igt@kms_flip@flip-vs-expired-vblank-interruptible@b-hdmi-a1.html

  * igt@kms_flip@flip-vs-expired-vblank@c-dp1:
    - shard-apl:          [PASS][45] -> [FAIL][46] ([i915#79])
   [45]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-apl7/igt@kms_flip@flip-vs-expired-vblank@c-dp1.html
   [46]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl2/igt@kms_flip@flip-vs-expired-vblank@c-dp1.html

  * igt@kms_flip_scaled_crc@flip-32bpp-ytile-to-32bpp-ytilegen12rcccs:
    - shard-apl:          NOTRUN -> [SKIP][47] ([fdo#109271] / [i915#2672])
   [47]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@kms_flip_scaled_crc@flip-32bpp-ytile-to-32bpp-ytilegen12rcccs.html

  * igt@kms_flip_scaled_crc@flip-64bpp-ytile-to-32bpp-ytilercccs:
    - shard-skl:          NOTRUN -> [SKIP][48] ([fdo#109271] / [i915#2672])
   [48]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl1/igt@kms_flip_scaled_crc@flip-64bpp-ytile-to-32bpp-ytilercccs.html

  * igt@kms_frontbuffer_tracking@fbc-1p-shrfb-fliptrack-mmap-gtt:
    - shard-skl:          NOTRUN -> [SKIP][49] ([fdo#109271]) +176 similar issues
   [49]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl9/igt@kms_frontbuffer_tracking@fbc-1p-shrfb-fliptrack-mmap-gtt.html

  * igt@kms_frontbuffer_tracking@fbc-2p-primscrn-spr-indfb-move:
    - shard-tglb:         NOTRUN -> [SKIP][50] ([fdo#111825]) +4 similar issues
   [50]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb2/igt@kms_frontbuffer_tracking@fbc-2p-primscrn-spr-indfb-move.html

  * igt@kms_frontbuffer_tracking@fbc-2p-scndscrn-shrfb-pgflip-blt:
    - shard-iclb:         NOTRUN -> [SKIP][51] ([fdo#109280]) +1 similar issue
   [51]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb2/igt@kms_frontbuffer_tracking@fbc-2p-scndscrn-shrfb-pgflip-blt.html

  * igt@kms_frontbuffer_tracking@fbcpsr-1p-primscrn-pri-shrfb-draw-mmap-cpu:
    - shard-glk:          NOTRUN -> [SKIP][52] ([fdo#109271]) +5 similar issues
   [52]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-glk3/igt@kms_frontbuffer_tracking@fbcpsr-1p-primscrn-pri-shrfb-draw-mmap-cpu.html

  * igt@kms_frontbuffer_tracking@psr-rgb101010-draw-mmap-wc:
    - shard-kbl:          NOTRUN -> [SKIP][53] ([fdo#109271]) +119 similar issues
   [53]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@kms_frontbuffer_tracking@psr-rgb101010-draw-mmap-wc.html

  * igt@kms_pipe_crc_basic@compare-crc-sanitycheck-pipe-d:
    - shard-skl:          NOTRUN -> [SKIP][54] ([fdo#109271] / [i915#533])
   [54]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl1/igt@kms_pipe_crc_basic@compare-crc-sanitycheck-pipe-d.html

  * igt@kms_plane@plane-panning-bottom-right-suspend@pipe-a-planes:
    - shard-apl:          [PASS][55] -> [DMESG-WARN][56] ([i915#180]) +4 similar issues
   [55]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-apl2/igt@kms_plane@plane-panning-bottom-right-suspend@pipe-a-planes.html
   [56]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl8/igt@kms_plane@plane-panning-bottom-right-suspend@pipe-a-planes.html

  * igt@kms_plane@plane-panning-bottom-right-suspend@pipe-b-planes:
    - shard-kbl:          [PASS][57] -> [DMESG-WARN][58] ([i915#180])
   [57]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl2/igt@kms_plane@plane-panning-bottom-right-suspend@pipe-b-planes.html
   [58]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl1/igt@kms_plane@plane-panning-bottom-right-suspend@pipe-b-planes.html

  * igt@kms_plane_alpha_blend@pipe-a-alpha-7efc:
    - shard-skl:          NOTRUN -> [FAIL][59] ([fdo#108145] / [i915#265]) +1 similar issue
   [59]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl9/igt@kms_plane_alpha_blend@pipe-a-alpha-7efc.html

  * igt@kms_plane_alpha_blend@pipe-b-alpha-7efc:
    - shard-kbl:          NOTRUN -> [FAIL][60] ([fdo#108145] / [i915#265]) +1 similar issue
   [60]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@kms_plane_alpha_blend@pipe-b-alpha-7efc.html

  * igt@kms_plane_alpha_blend@pipe-b-alpha-transparent-fb:
    - shard-skl:          NOTRUN -> [FAIL][61] ([i915#265])
   [61]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl1/igt@kms_plane_alpha_blend@pipe-b-alpha-transparent-fb.html

  * igt@kms_psr2_sf@overlay-plane-update-sf-dmg-area-1:
    - shard-tglb:         NOTRUN -> [SKIP][62] ([i915#2920]) +1 similar issue
   [62]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb3/igt@kms_psr2_sf@overlay-plane-update-sf-dmg-area-1.html

  * igt@kms_psr2_sf@overlay-primary-update-sf-dmg-area-2:
    - shard-apl:          NOTRUN -> [SKIP][63] ([fdo#109271] / [i915#658])
   [63]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-apl4/igt@kms_psr2_sf@overlay-primary-update-sf-dmg-area-2.html

  * igt@kms_psr2_sf@overlay-primary-update-sf-dmg-area-5:
    - shard-skl:          NOTRUN -> [SKIP][64] ([fdo#109271] / [i915#658]) +3 similar issues
   [64]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl10/igt@kms_psr2_sf@overlay-primary-update-sf-dmg-area-5.html

  * igt@kms_psr2_sf@primary-plane-update-sf-dmg-area-5:
    - shard-kbl:          NOTRUN -> [SKIP][65] ([fdo#109271] / [i915#658]) +1 similar issue
   [65]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl4/igt@kms_psr2_sf@primary-plane-update-sf-dmg-area-5.html
    - shard-iclb:         NOTRUN -> [SKIP][66] ([i915#658])
   [66]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb4/igt@kms_psr2_sf@primary-plane-update-sf-dmg-area-5.html

  * igt@kms_psr@psr2_cursor_render:
    - shard-iclb:         [PASS][67] -> [SKIP][68] ([fdo#109441]) +2 similar issues
   [67]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-iclb2/igt@kms_psr@psr2_cursor_render.html
   [68]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb1/igt@kms_psr@psr2_cursor_render.html

  * igt@kms_sysfs_edid_timing:
    - shard-skl:          NOTRUN -> [FAIL][69] ([IGT#2])
   [69]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl3/igt@kms_sysfs_edid_timing.html

  * igt@kms_vblank@pipe-a-ts-continuation-suspend:
    - shard-kbl:          [PASS][70] -> [DMESG-WARN][71] ([i915#180] / [i915#295])
   [70]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl1/igt@kms_vblank@pipe-a-ts-continuation-suspend.html
   [71]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl6/igt@kms_vblank@pipe-a-ts-continuation-suspend.html

  * igt@kms_writeback@writeback-invalid-parameters:
    - shard-kbl:          NOTRUN -> [SKIP][72] ([fdo#109271] / [i915#2437])
   [72]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@kms_writeback@writeback-invalid-parameters.html

  * igt@nouveau_crc@pipe-c-source-rg:
    - shard-iclb:         NOTRUN -> [SKIP][73] ([i915#2530])
   [73]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb8/igt@nouveau_crc@pipe-c-source-rg.html

  * igt@prime_vgem@basic-userptr:
    - shard-tglb:         NOTRUN -> [SKIP][74] ([i915#3301])
   [74]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb2/igt@prime_vgem@basic-userptr.html

  * igt@sysfs_clients@recycle-many:
    - shard-skl:          NOTRUN -> [SKIP][75] ([fdo#109271] / [i915#2994]) +1 similar issue
   [75]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl3/igt@sysfs_clients@recycle-many.html

  * igt@sysfs_clients@sema-50:
    - shard-kbl:          NOTRUN -> [SKIP][76] ([fdo#109271] / [i915#2994]) +2 similar issues
   [76]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl2/igt@sysfs_clients@sema-50.html

  
#### Possible fixes ####

  * igt@feature_discovery@psr2:
    - {shard-rkl}:        [SKIP][77] ([i915#658]) -> [PASS][78]
   [77]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@feature_discovery@psr2.html
   [78]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@feature_discovery@psr2.html

  * igt@gem_ctx_isolation@preservation-s3@rcs0:
    - shard-kbl:          [INCOMPLETE][79] ([i915#794]) -> [PASS][80]
   [79]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl4/igt@gem_ctx_isolation@preservation-s3@rcs0.html
   [80]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@gem_ctx_isolation@preservation-s3@rcs0.html

  * igt@gem_eio@unwedge-stress:
    - shard-iclb:         [TIMEOUT][81] ([i915#2481] / [i915#3070]) -> [PASS][82]
   [81]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-iclb8/igt@gem_eio@unwedge-stress.html
   [82]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb7/igt@gem_eio@unwedge-stress.html

  * igt@gem_exec_capture@pi@rcs0:
    - shard-skl:          [INCOMPLETE][83] ([i915#4547]) -> [PASS][84]
   [83]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-skl7/igt@gem_exec_capture@pi@rcs0.html
   [84]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl8/igt@gem_exec_capture@pi@rcs0.html

  * igt@gem_exec_fair@basic-deadline:
    - shard-glk:          [FAIL][85] ([i915#2846]) -> [PASS][86]
   [85]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-glk2/igt@gem_exec_fair@basic-deadline.html
   [86]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-glk5/igt@gem_exec_fair@basic-deadline.html

  * igt@gem_exec_fair@basic-none-solo@rcs0:
    - shard-kbl:          [FAIL][87] ([i915#2842]) -> [PASS][88]
   [87]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl3/igt@gem_exec_fair@basic-none-solo@rcs0.html
   [88]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl7/igt@gem_exec_fair@basic-none-solo@rcs0.html

  * igt@gem_exec_fair@basic-pace@bcs0:
    - shard-tglb:         [FAIL][89] ([i915#2842]) -> [PASS][90] +2 similar issues
   [89]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-tglb3/igt@gem_exec_fair@basic-pace@bcs0.html
   [90]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-tglb1/igt@gem_exec_fair@basic-pace@bcs0.html

  * igt@gem_exec_fair@basic-pace@rcs0:
    - shard-kbl:          [SKIP][91] ([fdo#109271]) -> [PASS][92]
   [91]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl6/igt@gem_exec_fair@basic-pace@rcs0.html
   [92]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl1/igt@gem_exec_fair@basic-pace@rcs0.html

  * igt@gem_exec_fair@basic-throttle@rcs0:
    - shard-iclb:         [FAIL][93] ([i915#2849]) -> [PASS][94]
   [93]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-iclb8/igt@gem_exec_fair@basic-throttle@rcs0.html
   [94]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb5/igt@gem_exec_fair@basic-throttle@rcs0.html

  * igt@i915_pm_backlight@basic-brightness:
    - {shard-rkl}:        [SKIP][95] ([i915#3012]) -> [PASS][96]
   [95]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@i915_pm_backlight@basic-brightness.html
   [96]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@i915_pm_backlight@basic-brightness.html

  * igt@i915_pm_rpm@dpms-mode-unset-lpsp:
    - {shard-rkl}:        ([SKIP][97], [SKIP][98]) ([i915#1397]) -> [PASS][99]
   [97]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-4/igt@i915_pm_rpm@dpms-mode-unset-lpsp.html
   [98]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-1/igt@i915_pm_rpm@dpms-mode-unset-lpsp.html
   [99]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@i915_pm_rpm@dpms-mode-unset-lpsp.html

  * igt@i915_pm_rpm@gem-pread:
    - {shard-rkl}:        [SKIP][100] ([fdo#109308]) -> [PASS][101]
   [100]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-1/igt@i915_pm_rpm@gem-pread.html
   [101]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@i915_pm_rpm@gem-pread.html

  * igt@i915_pm_rpm@modeset-lpsp-stress:
    - {shard-rkl}:        [SKIP][102] ([i915#1397]) -> [PASS][103]
   [102]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@i915_pm_rpm@modeset-lpsp-stress.html
   [103]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@i915_pm_rpm@modeset-lpsp-stress.html

  * igt@kms_ccs@pipe-b-crc-primary-rotation-180-y_tiled_gen12_rc_ccs_cc:
    - {shard-rkl}:        [SKIP][104] ([i915#1845]) -> [PASS][105] +35 similar issues
   [104]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_ccs@pipe-b-crc-primary-rotation-180-y_tiled_gen12_rc_ccs_cc.html
   [105]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_ccs@pipe-b-crc-primary-rotation-180-y_tiled_gen12_rc_ccs_cc.html

  * igt@kms_color@pipe-a-ctm-0-75:
    - {shard-rkl}:        [SKIP][106] ([i915#1149] / [i915#1849] / [i915#4070]) -> [PASS][107] +3 similar issues
   [106]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_color@pipe-a-ctm-0-75.html
   [107]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_color@pipe-a-ctm-0-75.html

  * igt@kms_color@pipe-b-ctm-0-5:
    - {shard-rkl}:        ([SKIP][108], [SKIP][109]) ([i915#1149] / [i915#1849] / [i915#4070] / [i915#4098]) -> [PASS][110]
   [108]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_color@pipe-b-ctm-0-5.html
   [109]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-4/igt@kms_color@pipe-b-ctm-0-5.html
   [110]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_color@pipe-b-ctm-0-5.html

  * igt@kms_cursor_crc@pipe-b-cursor-64x21-onscreen:
    - {shard-rkl}:        [SKIP][111] ([fdo#112022] / [i915#4070]) -> [PASS][112] +8 similar issues
   [111]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_cursor_crc@pipe-b-cursor-64x21-onscreen.html
   [112]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_cursor_crc@pipe-b-cursor-64x21-onscreen.html

  * igt@kms_cursor_crc@pipe-b-cursor-64x21-random:
    - {shard-rkl}:        ([SKIP][113], [SKIP][114]) ([fdo#112022] / [i915#4070]) -> [PASS][115] +4 similar issues
   [113]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-1/igt@kms_cursor_crc@pipe-b-cursor-64x21-random.html
   [114]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-4/igt@kms_cursor_crc@pipe-b-cursor-64x21-random.html
   [115]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_cursor_crc@pipe-b-cursor-64x21-random.html

  * igt@kms_cursor_edge_walk@pipe-b-256x256-right-edge:
    - {shard-rkl}:        [SKIP][116] ([i915#1849] / [i915#4070]) -> [PASS][117] +7 similar issues
   [116]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_cursor_edge_walk@pipe-b-256x256-right-edge.html
   [117]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_cursor_edge_walk@pipe-b-256x256-right-edge.html

  * igt@kms_cursor_legacy@cursora-vs-flipa-toggle:
    - {shard-rkl}:        [SKIP][118] ([fdo#111825] / [i915#4070]) -> [PASS][119]
   [118]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-1/igt@kms_cursor_legacy@cursora-vs-flipa-toggle.html
   [119]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_cursor_legacy@cursora-vs-flipa-toggle.html

  * igt@kms_cursor_legacy@flip-vs-cursor-atomic-transitions-varying-size:
    - shard-skl:          [FAIL][120] ([i915#2346] / [i915#533]) -> [PASS][121]
   [120]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-skl6/igt@kms_cursor_legacy@flip-vs-cursor-atomic-transitions-varying-size.html
   [121]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl6/igt@kms_cursor_legacy@flip-vs-cursor-atomic-transitions-varying-size.html

  * igt@kms_cursor_legacy@flip-vs-cursor-crc-atomic:
    - {shard-rkl}:        ([SKIP][122], [SKIP][123]) ([fdo#111825] / [i915#4070]) -> [PASS][124] +2 similar issues
   [122]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-1/igt@kms_cursor_legacy@flip-vs-cursor-crc-atomic.html
   [123]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-4/igt@kms_cursor_legacy@flip-vs-cursor-crc-atomic.html
   [124]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_cursor_legacy@flip-vs-cursor-crc-atomic.html

  * igt@kms_cursor_legacy@flip-vs-cursor-toggle:
    - shard-skl:          [FAIL][125] ([i915#2346]) -> [PASS][126]
   [125]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-skl3/igt@kms_cursor_legacy@flip-vs-cursor-toggle.html
   [126]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-skl4/igt@kms_cursor_legacy@flip-vs-cursor-toggle.html

  * igt@kms_draw_crc@draw-method-xrgb2101010-mmap-gtt-xtiled:
    - {shard-rkl}:        [SKIP][127] ([fdo#111314]) -> [PASS][128] +9 similar issues
   [127]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_draw_crc@draw-method-xrgb2101010-mmap-gtt-xtiled.html
   [128]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_draw_crc@draw-method-xrgb2101010-mmap-gtt-xtiled.html

  * igt@kms_draw_crc@draw-method-xrgb2101010-mmap-wc-ytiled:
    - {shard-rkl}:        ([SKIP][129], [SKIP][130]) ([fdo#111314] / [i915#4098]) -> [PASS][131] +1 similar issue
   [129]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-1/igt@kms_draw_crc@draw-method-xrgb2101010-mmap-wc-ytiled.html
   [130]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-4/igt@kms_draw_crc@draw-method-xrgb2101010-mmap-wc-ytiled.html
   [131]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_draw_crc@draw-method-xrgb2101010-mmap-wc-ytiled.html

  * igt@kms_fbcon_fbt@fbc-suspend:
    - {shard-rkl}:        ([SKIP][132], [SKIP][133]) ([i915#1849] / [i915#4098]) -> [PASS][134] +10 similar issues
   [132]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-2/igt@kms_fbcon_fbt@fbc-suspend.html
   [133]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-rkl-4/igt@kms_fbcon_fbt@fbc-suspend.html
   [134]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-rkl-6/igt@kms_fbcon_fbt@fbc-suspend.html

  * igt@kms_flip@flip-vs-suspend-interruptible@c-dp1:
    - shard-kbl:          [INCOMPLETE][135] ([i915#636]) -> [PASS][136]
   [135]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl2/igt@kms_flip@flip-vs-suspend-interruptible@c-dp1.html
   [136]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-kbl4/igt@kms_flip@flip-vs-suspend-interruptible@c-dp1.html

  * igt@kms_flip_scaled_crc@flip-32bpp-ytileccs-to-64bpp-ytile:
    - shard-iclb:         [SKIP][137] ([i915#3701]) -> [PASS][138] +1 similar issue
   [137]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-iclb2/igt@kms_flip_scaled_crc@flip-32bpp-ytileccs-to-64bpp-ytile.html
   [138]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/shard-iclb8/igt@kms_flip_scaled_crc@flip-32bpp-ytileccs-to-64bpp-ytile.html

  * igt@kms_frontbuffer_tracking@fbc-suspend:
    - shard-kbl:          [DMESG-WARN][139] ([i915#180]) -> [PASS][140] +3 similar issues
   [139]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_10959/shard-kbl1/

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21740/index.html

[-- Attachment #2: Type: text/html, Size: 33371 bytes --]

Re: [Intel-gfx] [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Kees Cook]

On Fri, Dec 03, 2021 at 04:28:56PM +0100, Thierry Reding wrote:
> On Fri, Dec 03, 2021 at 01:25:17AM -0800, Kees Cook wrote:
> > The link_status array was not large enough to read the Adjust Request
> > Post Cursor2 register. Adjust the size to include it. Found with a
> > -Warray-bounds build:
> > 
> > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
> > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
> >    59 |         return link_status[r - DP_LANE0_1_STATUS];
> >       |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
> > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
> >   147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
> >       |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 
> > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > v2: Fix missed array size change in intel_dp_check_mst_status()
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
> >  include/drm/drm_dp_helper.h             | 10 +++++++++-
> >  2 files changed, 13 insertions(+), 5 deletions(-)
> 
> This sounds very familiar and I vaguely recall typing up a patch like
> that a long time ago. But I obviously failed because that never seems
> to have made it upstream.
> 
> Or perhaps I'm misremembering and was thinking about this instead:
> 
> 	https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/338590/

Oh! Yeah, that's the same thing. Looks like that never made its way
upstream. :(

> 
> Bonus points for adding that comment with background information on why
> we need this.

Thanks! Yeah, I needed to really convince myself everything added up and
made sense, and figured I should try to capture that research. ;)

> Reviewed-by: Thierry Reding <treding@nvidia.com>

Thanks!

-Kees

-- 
Kees Cook

Re: [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Kees Cook]

On Fri, Dec 03, 2021 at 04:28:56PM +0100, Thierry Reding wrote:
> On Fri, Dec 03, 2021 at 01:25:17AM -0800, Kees Cook wrote:
> > The link_status array was not large enough to read the Adjust Request
> > Post Cursor2 register. Adjust the size to include it. Found with a
> > -Warray-bounds build:
> > 
> > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
> > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
> >    59 |         return link_status[r - DP_LANE0_1_STATUS];
> >       |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
> > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
> >   147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
> >       |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 
> > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > v2: Fix missed array size change in intel_dp_check_mst_status()
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
> >  include/drm/drm_dp_helper.h             | 10 +++++++++-
> >  2 files changed, 13 insertions(+), 5 deletions(-)
> 
> This sounds very familiar and I vaguely recall typing up a patch like
> that a long time ago. But I obviously failed because that never seems
> to have made it upstream.
> 
> Or perhaps I'm misremembering and was thinking about this instead:
> 
> 	https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/338590/

Oh! Yeah, that's the same thing. Looks like that never made its way
upstream. :(

> 
> Bonus points for adding that comment with background information on why
> we need this.

Thanks! Yeah, I needed to really convince myself everything added up and
made sense, and figured I should try to capture that research. ;)

> Reviewed-by: Thierry Reding <treding@nvidia.com>

Thanks!

-Kees

-- 
Kees Cook

Re: [PATCH v2] drm/dp: Actually read Adjust Request Post Cursor2 register

[Kees Cook]

On Fri, Dec 03, 2021 at 04:28:56PM +0100, Thierry Reding wrote:
> On Fri, Dec 03, 2021 at 01:25:17AM -0800, Kees Cook wrote:
> > The link_status array was not large enough to read the Adjust Request
> > Post Cursor2 register. Adjust the size to include it. Found with a
> > -Warray-bounds build:
> > 
> > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':
> > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]
> >    59 |         return link_status[r - DP_LANE0_1_STATUS];
> >       |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
> > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'
> >   147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
> >       |                                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 
> > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > v2: Fix missed array size change in intel_dp_check_mst_status()
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp.c |  8 ++++----
> >  include/drm/drm_dp_helper.h             | 10 +++++++++-
> >  2 files changed, 13 insertions(+), 5 deletions(-)
> 
> This sounds very familiar and I vaguely recall typing up a patch like
> that a long time ago. But I obviously failed because that never seems
> to have made it upstream.
> 
> Or perhaps I'm misremembering and was thinking about this instead:
> 
> 	https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/338590/

Oh! Yeah, that's the same thing. Looks like that never made its way
upstream. :(

> 
> Bonus points for adding that comment with background information on why
> we need this.

Thanks! Yeah, I needed to really convince myself everything added up and
made sense, and figured I should try to capture that research. ;)

> Reviewed-by: Thierry Reding <treding@nvidia.com>

Thanks!

-Kees

-- 
Kees Cook