Re: [PATCH v2 5/5] drm/i915: Introduce intel_bo_fbdev_bios_fb_takeover()

Hey,

On 7/23/26 11:06, Shankar, Uma wrote:
> 
> 
>> -----Original Message-----
>> From: Intel-xe <[email protected]> On Behalf Of Maarten
>> Lankhorst
>> Sent: Tuesday, July 21, 2026 7:56 PM
>> To: [email protected]
>> Cc: [email protected]; Maarten Lankhorst <[email protected]>; Ville
>> Syrjälä <[email protected]>
>> Subject: [PATCH v2 5/5] drm/i915: Introduce intel_bo_fbdev_bios_fb_takeover()
>>
>> Pull the "do we want to use stolen for the BIOS FB?" checks into a new
>> intel_bo_fbdev_bios_fb_takeover() helper, and defer that decision until we're ready
>> to reallocate the fbdev FB. This way even if we don't want to ultimately use the
>> BIOS FB we'll keep the plane enabled until the replacement FB is ready. Should
>> hopefully result in fewer display blinks during boot.
>>
>> Additionally, on some platforms this allows us to re-create the framebuffer when
>> stolen memory is not suitable, using the blitter engine to copy the contents to
>> system memory without causing any flickering by not preserving the stolen
>> memory allocation.
>>
>> Based on a similar patch by Ville, that introduced intel_bo_fbdev_bios_fb_ok().
> 
> Looks Good to me.
> Reviewed-by: Uma Shankar <[email protected]>
> 
> Please get an ack from someone from Core KMD as well.
> 
> @B S, Karthik Can we ask someone to check and give a Tested-by from validation
> side for this series.

I've been testing a bit locally, but I see a small flicker while transitioning
from stolen to system memory.

I need to figure out why that happens, as that should have been prevented by
the call to drm_gem_plane_helper_prepare_fb() in prepare_plane_fb()
before the atomic flip.