[PATCH] drm/xe/display: fix oops in suspend/shutdown without display

[PATCH] drm/xe/display: fix oops in suspend/shutdown without display

[Jani Nikula]

The xe driver keeps track of whether to probe display, and whether
display hardware is there, using xe->info.probe_display. It gets set to
false if there's no display after intel_display_device_probe(). However,
the display may also be disabled via fuses, detected at a later time in
intel_display_device_info_runtime_init().

In this case, the xe driver does for_each_intel_crtc() on uninitialized
mode config in xe_display_flush_cleanup_work(), leading to a NULL
pointer dereference, and generally calls display code with display info
cleared.

Check for intel_display_device_present() after
intel_display_device_info_runtime_init(), and reset
xe->info.probe_display as necessary. Also do unset_display_features()
for completeness, although display runtime init has already done
that. This will need to be unified across all cases later.

Move intel_display_device_info_runtime_init() call slightly earlier,
similar to i915, to avoid a bunch of unnecessary setup for no display
cases.

Note #1: The xe driver has no business doing low level display plumbing
like for_each_intel_crtc() to begin with. It all needs to happen in
display code.

Note #2: The actual bug is present already in commit 44e694958b95
("drm/xe/display: Implement display support"), but the oops was likely
introduced later at commit ddf6492e0e50 ("drm/xe/display: Make display
suspend/resume work on discrete").

Fixes: 44e694958b95 ("drm/xe/display: Implement display support")
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/7904
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/6150
Cc: <stable@vger.kernel.org> # v6.8+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/xe/display/xe_display.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
index 053abd6f6514..5f25932730f4 100644
--- a/drivers/gpu/drm/xe/display/xe_display.c
+++ b/drivers/gpu/drm/xe/display/xe_display.c
@@ -104,6 +104,15 @@ int xe_display_init_early(struct xe_device *xe)
 
 	intel_display_driver_early_probe(display);
 
+	intel_display_device_info_runtime_init(display);
+
+	/* Display may have been disabled at runtime init */
+	if (!intel_display_device_present(display)) {
+		xe->info.probe_display = false;
+		unset_display_features(xe);
+		return 0;
+	}
+
 	/* Early display init.. */
 	intel_opregion_setup(display);
 
@@ -117,8 +126,6 @@ int xe_display_init_early(struct xe_device *xe)
 
 	intel_bw_init_hw(display);
 
-	intel_display_device_info_runtime_init(display);
-
 	err = intel_display_driver_probe_noirq(display);
 	if (err)
 		goto err_opregion;
-- 
2.47.3

RE: [PATCH] drm/xe/display: fix oops in suspend/shutdown without display

[Kandpal, Suraj]

> Subject: [PATCH] drm/xe/display: fix oops in suspend/shutdown without
> display
> 
> The xe driver keeps track of whether to probe display, and whether display
> hardware is there, using xe->info.probe_display. It gets set to false if there's no
> display after intel_display_device_probe(). However, the display may also be
> disabled via fuses, detected at a later time in
> intel_display_device_info_runtime_init().
> 
> In this case, the xe driver does for_each_intel_crtc() on uninitialized mode
> config in xe_display_flush_cleanup_work(), leading to a NULL pointer
> dereference, and generally calls display code with display info cleared.
> 
> Check for intel_display_device_present() after
> intel_display_device_info_runtime_init(), and reset
> xe->info.probe_display as necessary. Also do unset_display_features()
> for completeness, although display runtime init has already done that. This will
> need to be unified across all cases later.
> 
> Move intel_display_device_info_runtime_init() call slightly earlier, similar to
> i915, to avoid a bunch of unnecessary setup for no display cases.
> 
> Note #1: The xe driver has no business doing low level display plumbing like
> for_each_intel_crtc() to begin with. It all needs to happen in display code.
> 
> Note #2: The actual bug is present already in commit 44e694958b95
> ("drm/xe/display: Implement display support"), but the oops was likely
> introduced later at commit ddf6492e0e50 ("drm/xe/display: Make display
> suspend/resume work on discrete").
> 
> Fixes: 44e694958b95 ("drm/xe/display: Implement display support")
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/7904
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/6150
> Cc: <stable@vger.kernel.org> # v6.8+
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

LGTM,
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>

> ---
>  drivers/gpu/drm/xe/display/xe_display.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/display/xe_display.c
> b/drivers/gpu/drm/xe/display/xe_display.c
> index 053abd6f6514..5f25932730f4 100644
> --- a/drivers/gpu/drm/xe/display/xe_display.c
> +++ b/drivers/gpu/drm/xe/display/xe_display.c
> @@ -104,6 +104,15 @@ int xe_display_init_early(struct xe_device *xe)
> 
>  	intel_display_driver_early_probe(display);
> 
> +	intel_display_device_info_runtime_init(display);
> +
> +	/* Display may have been disabled at runtime init */
> +	if (!intel_display_device_present(display)) {
> +		xe->info.probe_display = false;
> +		unset_display_features(xe);
> +		return 0;
> +	}
> +
>  	/* Early display init.. */
>  	intel_opregion_setup(display);
> 
> @@ -117,8 +126,6 @@ int xe_display_init_early(struct xe_device *xe)
> 
>  	intel_bw_init_hw(display);
> 
> -	intel_display_device_info_runtime_init(display);
> -
>  	err = intel_display_driver_probe_noirq(display);
>  	if (err)
>  		goto err_opregion;
> --
> 2.47.3

RE: [PATCH] drm/xe/display: fix oops in suspend/shutdown without display

[Jani Nikula]

On Fri, 15 May 2026, "Kandpal, Suraj" <suraj.kandpal@intel.com> wrote:
>> Subject: [PATCH] drm/xe/display: fix oops in suspend/shutdown without
>> display
>> 
>> The xe driver keeps track of whether to probe display, and whether display
>> hardware is there, using xe->info.probe_display. It gets set to false if there's no
>> display after intel_display_device_probe(). However, the display may also be
>> disabled via fuses, detected at a later time in
>> intel_display_device_info_runtime_init().
>> 
>> In this case, the xe driver does for_each_intel_crtc() on uninitialized mode
>> config in xe_display_flush_cleanup_work(), leading to a NULL pointer
>> dereference, and generally calls display code with display info cleared.
>> 
>> Check for intel_display_device_present() after
>> intel_display_device_info_runtime_init(), and reset
>> xe->info.probe_display as necessary. Also do unset_display_features()
>> for completeness, although display runtime init has already done that. This will
>> need to be unified across all cases later.
>> 
>> Move intel_display_device_info_runtime_init() call slightly earlier, similar to
>> i915, to avoid a bunch of unnecessary setup for no display cases.
>> 
>> Note #1: The xe driver has no business doing low level display plumbing like
>> for_each_intel_crtc() to begin with. It all needs to happen in display code.
>> 
>> Note #2: The actual bug is present already in commit 44e694958b95
>> ("drm/xe/display: Implement display support"), but the oops was likely
>> introduced later at commit ddf6492e0e50 ("drm/xe/display: Make display
>> suspend/resume work on discrete").
>> 
>> Fixes: 44e694958b95 ("drm/xe/display: Implement display support")
>> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/7904
>> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/6150
>> Cc: <stable@vger.kernel.org> # v6.8+
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> LGTM,
> Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>

Thanks, pushed to drm-intel-next (and not drm-xe-next) to avoid
conflicts with other display changes.

BR,
Jani.

>
>> ---
>>  drivers/gpu/drm/xe/display/xe_display.c | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/xe/display/xe_display.c
>> b/drivers/gpu/drm/xe/display/xe_display.c
>> index 053abd6f6514..5f25932730f4 100644
>> --- a/drivers/gpu/drm/xe/display/xe_display.c
>> +++ b/drivers/gpu/drm/xe/display/xe_display.c
>> @@ -104,6 +104,15 @@ int xe_display_init_early(struct xe_device *xe)
>> 
>>  	intel_display_driver_early_probe(display);
>> 
>> +	intel_display_device_info_runtime_init(display);
>> +
>> +	/* Display may have been disabled at runtime init */
>> +	if (!intel_display_device_present(display)) {
>> +		xe->info.probe_display = false;
>> +		unset_display_features(xe);
>> +		return 0;
>> +	}
>> +
>>  	/* Early display init.. */
>>  	intel_opregion_setup(display);
>> 
>> @@ -117,8 +126,6 @@ int xe_display_init_early(struct xe_device *xe)
>> 
>>  	intel_bw_init_hw(display);
>> 
>> -	intel_display_device_info_runtime_init(display);
>> -
>>  	err = intel_display_driver_probe_noirq(display);
>>  	if (err)
>>  		goto err_opregion;
>> --
>> 2.47.3
>

-- 
Jani Nikula, Intel