[PATCH] drm/xe/display: Remove invalid initial plane PTE check for iGPU

[PATCH] drm/xe/display: Remove invalid initial plane PTE check for iGPU

[Andrew Zhou]

Pantherlake intergrated graphics can have the XE_GGTT_PTEDM bit set
in the BIOS-initialised framebuffer PTE. The new validation rejects
this and fails to create the initial frambuffer, resulting in static.

Remove the too-strict validation.

Signed-off-by: Andrew Zhou <zhoulol888@gmail.com>
Tested-by: Andrew Zhou <zhoulol888@gmail.com>
Tested-on: Intel Core Ultra X7 358H, integrated graphics, B0 stepping
---
 drivers/gpu/drm/xe/display/xe_initial_plane.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/gpu/drm/xe/display/xe_initial_plane.c b/drivers/gpu/drm/xe/display/xe_initial_plane.c
index 0f86b7303..8c95dc4e6 100644
--- a/drivers/gpu/drm/xe/display/xe_initial_plane.c
+++ b/drivers/gpu/drm/xe/display/xe_initial_plane.c
@@ -85,7 +85,6 @@ initial_plane_bo(struct xe_device *xe,
 			    &phys_base);
 	} else {
 		struct ttm_resource_manager *stolen;
-		u64 pte;
 
 		stolen = ttm_manager_type(&xe->ttm, XE_PL_STOLEN);
 		if (!stolen) {
@@ -93,13 +92,6 @@ initial_plane_bo(struct xe_device *xe,
 			return NULL;
 		}
 
-		pte = xe_ggtt_read_pte(tile0->mem.ggtt, base);
-
-		if (is_pte_local(pte) != need_pte_local(xe)) {
-			drm_err(&xe->drm, "Initial plane PTE has bad local memory bit\n");
-			return NULL;
-		}
-
 		phys_base = base;
 		flags |= XE_BO_FLAG_STOLEN;
 
-- 
2.55.0

Re: [PATCH] drm/xe/display: Remove invalid initial plane PTE check for iGPU

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The patch removes the validation from the integrated graphics path, rendering the `has_lmembar()` logic completely dead and meaningless.
--

commit b290f7e32abe43d35ac4f5def3b10e9bcf641a88
Author: Andrew Zhou <zhoulol888@gmail.com>

drm/xe/display: Remove invalid initial plane PTE check for iGPU

This commit removes the initial plane PTE local memory validation for
integrated graphics, as Pantherlake can have the XE_GGTT_PTEDM bit set.
The check was causing a failure to create the initial framebuffer.

> diff --git a/drivers/gpu/drm/xe/display/xe_initial_plane.c b/drivers/gpu/drm/xe/display/xe_initial_plane.c
> index 0f86b73036d03..8c95dc4e6f2ef 100644
> --- a/drivers/gpu/drm/xe/display/xe_initial_plane.c
> +++ b/drivers/gpu/drm/xe/display/xe_initial_plane.c

[ ... ]

> @@ -93,13 +92,6 @@ initial_plane_bo(struct xe_device *xe,
>  			return NULL;
>  		}
>  
> -		pte = xe_ggtt_read_pte(tile0->mem.ggtt, base);
> -
> -		if (is_pte_local(pte) != need_pte_local(xe)) {
> -			drm_err(&xe->drm, "Initial plane PTE has bad local memory bit\n");
> -			return NULL;
> -		}
> -

[Severity: Low]
Does this leave need_pte_local() with dead logic?

By removing this validation from the integrated graphics path (!IS_DGFX(xe)),
the only remaining caller of need_pte_local() is inside the earlier 
if (IS_DGFX(xe)) branch in initial_plane_bo().

Because need_pte_local() is defined as:

static bool need_pte_local(struct xe_device *xe)
{
	return IS_DGFX(xe) || has_lmembar(xe);
}

It will now unconditionally evaluate to true when called, rendering the
has_lmembar(xe) check completely meaningless. 

Should need_pte_local() and its underlying logic be simplified or removed 
as well to prevent confusion?

>  		phys_base = base;
>  		flags |= XE_BO_FLAG_STOLEN;
>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260905142500.17666-1-zhoulol888@gmail.com?part=1

✗ LGCI.VerificationFailed: failure for drm/xe/display: Remove invalid initial plane PTE check for iGPU

[Patchwork]

== Series Details ==

Series: drm/xe/display: Remove invalid initial plane PTE check for iGPU
URL   : https://patchwork.freedesktop.org/series/173618/
State : failure

== Summary ==

Series author address 'zhoulol888@gmail.com' is not on the allowlist, which prevents CI from being automatically triggered.
If you want CI to run for this series, ask Patchwork project owners to click 'retest' on the series in Patchwork.
Exception occurred during validation, bailing out!
Build URL: http://gfx-ci.igk.intel.com:8080/job/CI_PW_kernel/187020/ (on built-in)