* [PATCH] drm/amd/display: Use separate iterator for preferred mode lookup
@ 2026-10-08 5:17 Yibiao Li
2026-10-16 15:50 ` Alex Hung
0 siblings, 1 reply; 3+ messages in thread
From: Yibiao Li @ 2026-10-08 5:17 UTC (permalink / raw)
To: amd-gfx, Harry Wentland, Leo Li
Cc: Rodrigo Siqueira, Alex Deucher, Christian König, dri-devel,
linux-kernel, kernel test robot
From: Yibiao Li <biaobiao2233@gmail.com>
create_stream_for_sink() uses preferred_mode both as the list iterator
and as the selected mode. This triggers a false positive from
scripts/coccinelle/iterators/use_after_iter.cocci: native_mode_found
already ensures that an exhausted iterator is replaced before use.
Use a separate iterator and assign preferred_mode only when a preferred
entry is found. This keeps the selected mode separate from the iterator
state and makes native_mode_found unnecessary. Preserve the fallback to
the first entry, or NULL when the list is empty.
No functional change intended.
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202609190901.yKTzhsGz-lkp@intel.com/
Assisted-by: LLM coccinelle
Signed-off-by: Yibiao Li <biaobiao2233@gmail.com>
---
.../drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
index d386bb1475..ceea8fe481 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
@@ -1453,12 +1453,12 @@ create_stream_for_sink(struct drm_connector *connector,
struct drm_device *dev = connector->dev;
struct amdgpu_dm_connector *aconnector = NULL;
struct drm_display_mode *preferred_mode = NULL;
+ struct drm_display_mode *connector_mode;
const struct drm_connector_state *con_state = &dm_state->base;
struct dc_stream_state *stream = NULL;
struct drm_display_mode mode;
struct drm_display_mode saved_mode;
struct drm_display_mode *freesync_mode = NULL;
- bool native_mode_found = false;
bool recalculate_timing = false;
bool scale = dm_state->scaling != RMX_OFF;
int mode_refresh;
@@ -1509,14 +1509,14 @@ create_stream_for_sink(struct drm_connector *connector,
stream->timing.flags.LTE_340MCSC_SCRAMBLE =
connector->display_info.hdmi.scdc.scrambling.low_rates;
- list_for_each_entry(preferred_mode, &connector->modes, head) {
+ list_for_each_entry(connector_mode, &connector->modes, head) {
/* Search for preferred mode */
- if (preferred_mode->type & DRM_MODE_TYPE_PREFERRED) {
- native_mode_found = true;
+ if (connector_mode->type & DRM_MODE_TYPE_PREFERRED) {
+ preferred_mode = connector_mode;
break;
}
}
- if (!native_mode_found)
+ if (!preferred_mode)
preferred_mode = list_first_entry_or_null(
&connector->modes,
struct drm_display_mode,
--
2.43.0
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] drm/amd/display: Use separate iterator for preferred mode lookup
2026-10-08 5:17 [PATCH] drm/amd/display: Use separate iterator for preferred mode lookup Yibiao Li
@ 2026-10-16 15:50 ` Alex Hung
2026-10-16 17:37 ` Yibiao Li
0 siblings, 1 reply; 3+ messages in thread
From: Alex Hung @ 2026-10-16 15:50 UTC (permalink / raw)
To: Yibiao Li, amd-gfx, Harry Wentland, Leo Li
Cc: Rodrigo Siqueira, Alex Deucher, Christian König, dri-devel,
linux-kernel, kernel test robot
Reviewed-by: Alex Hung <alex.hung@amd.com>
On 10/7/26 23:17, Yibiao Li wrote:
> [Some people who received this message don't often get email from biaobiao2233@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> From: Yibiao Li <biaobiao2233@gmail.com>
>
> create_stream_for_sink() uses preferred_mode both as the list iterator
> and as the selected mode. This triggers a false positive from
> scripts/coccinelle/iterators/use_after_iter.cocci: native_mode_found
> already ensures that an exhausted iterator is replaced before use.
>
> Use a separate iterator and assign preferred_mode only when a preferred
> entry is found. This keeps the selected mode separate from the iterator
> state and makes native_mode_found unnecessary. Preserve the fallback to
> the first entry, or NULL when the list is empty.
>
> No functional change intended.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Link: https://lore.kernel.org/oe-kbuild-all/202609190901.yKTzhsGz-lkp@intel.com/
> Assisted-by: LLM coccinelle
> Signed-off-by: Yibiao Li <biaobiao2233@gmail.com>
> ---
> .../drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> index d386bb1475..ceea8fe481 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> @@ -1453,12 +1453,12 @@ create_stream_for_sink(struct drm_connector *connector,
> struct drm_device *dev = connector->dev;
> struct amdgpu_dm_connector *aconnector = NULL;
> struct drm_display_mode *preferred_mode = NULL;
> + struct drm_display_mode *connector_mode;
> const struct drm_connector_state *con_state = &dm_state->base;
> struct dc_stream_state *stream = NULL;
> struct drm_display_mode mode;
> struct drm_display_mode saved_mode;
> struct drm_display_mode *freesync_mode = NULL;
> - bool native_mode_found = false;
> bool recalculate_timing = false;
> bool scale = dm_state->scaling != RMX_OFF;
> int mode_refresh;
> @@ -1509,14 +1509,14 @@ create_stream_for_sink(struct drm_connector *connector,
> stream->timing.flags.LTE_340MCSC_SCRAMBLE =
> connector->display_info.hdmi.scdc.scrambling.low_rates;
>
> - list_for_each_entry(preferred_mode, &connector->modes, head) {
> + list_for_each_entry(connector_mode, &connector->modes, head) {
> /* Search for preferred mode */
> - if (preferred_mode->type & DRM_MODE_TYPE_PREFERRED) {
> - native_mode_found = true;
> + if (connector_mode->type & DRM_MODE_TYPE_PREFERRED) {
> + preferred_mode = connector_mode;
> break;
> }
> }
> - if (!native_mode_found)
> + if (!preferred_mode)
> preferred_mode = list_first_entry_or_null(
> &connector->modes,
> struct drm_display_mode,
> --
> 2.43.0
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] drm/amd/display: Use separate iterator for preferred mode lookup
2026-10-16 15:50 ` Alex Hung
@ 2026-10-16 17:37 ` Yibiao Li
0 siblings, 0 replies; 3+ messages in thread
From: Yibiao Li @ 2026-10-16 17:37 UTC (permalink / raw)
To: Alex Hung
Cc: amd-gfx, Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, dri-devel, linux-kernel, kernel test robot
On Fri, Oct 16, 2026 at 09:50:44AM -0600, Alex Hung wrote:
> Reviewed-by: Alex Hung <alex.hung@amd.com>
Thanks for the review, Alex!
Best regards,
Yibiao
On Fri, 16 Oct 2026 09:50:44 -0600, Alex Hung <alex.hung@amd.com> wrote:
> Reviewed-by: Alex Hung <alex.hung@amd.com>
>
> On 10/7/26 23:17, Yibiao Li wrote:
> > [Some people who received this message don't often get email from biaobiao2233@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> >
> > From: Yibiao Li <biaobiao2233@gmail.com>
> >
> > create_stream_for_sink() uses preferred_mode both as the list iterator
> > and as the selected mode. This triggers a false positive from
> > scripts/coccinelle/iterators/use_after_iter.cocci: native_mode_found
> > already ensures that an exhausted iterator is replaced before use.
> >
> > Use a separate iterator and assign preferred_mode only when a preferred
> > entry is found. This keeps the selected mode separate from the iterator
> > state and makes native_mode_found unnecessary. Preserve the fallback to
> > the first entry, or NULL when the list is empty.
> >
> > No functional change intended.
> >
> > Reported-by: kernel test robot <lkp@intel.com>
> > Link: https://lore.kernel.org/oe-kbuild-all/202609190901.yKTzhsGz-lkp@intel.com/
> > Assisted-by: LLM coccinelle
> > Signed-off-by: Yibiao Li <biaobiao2233@gmail.com>
> > ---
> > .../drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> > index d386bb1475..ceea8fe481 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> > @@ -1453,12 +1453,12 @@ create_stream_for_sink(struct drm_connector *connector,
> > struct drm_device *dev = connector->dev;
> > struct amdgpu_dm_connector *aconnector = NULL;
> > struct drm_display_mode *preferred_mode = NULL;
> > + struct drm_display_mode *connector_mode;
> > const struct drm_connector_state *con_state = &dm_state->base;
> > struct dc_stream_state *stream = NULL;
> > struct drm_display_mode mode;
> > struct drm_display_mode saved_mode;
> > struct drm_display_mode *freesync_mode = NULL;
> > - bool native_mode_found = false;
> > bool recalculate_timing = false;
> > bool scale = dm_state->scaling != RMX_OFF;
> > int mode_refresh;
> > @@ -1509,14 +1509,14 @@ create_stream_for_sink(struct drm_connector *connector,
> > stream->timing.flags.LTE_340MCSC_SCRAMBLE =
> > connector->display_info.hdmi.scdc.scrambling.low_rates;
> >
> > - list_for_each_entry(preferred_mode, &connector->modes, head) {
> > + list_for_each_entry(connector_mode, &connector->modes, head) {
> > /* Search for preferred mode */
> > - if (preferred_mode->type & DRM_MODE_TYPE_PREFERRED) {
> > - native_mode_found = true;
> > + if (connector_mode->type & DRM_MODE_TYPE_PREFERRED) {
> > + preferred_mode = connector_mode;
> > break;
> > }
> > }
> > - if (!native_mode_found)
> > + if (!preferred_mode)
> > preferred_mode = list_first_entry_or_null(
> > &connector->modes,
> > struct drm_display_mode,
> > --
> > 2.43.0
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-10-16 17:37 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2026-10-08 5:17 [PATCH] drm/amd/display: Use separate iterator for preferred mode lookup Yibiao Li
2026-10-16 15:50 ` Alex Hung
2026-10-16 17:37 ` Yibiao Li
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