Re: [PATCH 2/9] drm/{i915, xe}/fbdev: add intel_fbdev_fb_pitch_align()

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Oct 13, 2025 at 04:52:04PM +0300, Jani Nikula wrote:
> On Thu, 18 Sep 2025, Jani Nikula <jani.nikula@intel.com> wrote:
> > On Tue, 16 Sep 2025, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> >> For now I'd be happy if someone just nukes that bogus page alignemnt
> >> of the stride on xe, allowing i915 and xe to use the same code here.
> >
> > I hope just [1] is enough for this.
> >
> > [1] https://lore.kernel.org/r/7f4972104de8b179d5724ae83892ee294d3f3fd3.1758184771.git.jani.nikula@intel.com
> 
> So that regressed [2]. (Bisected internally, unfortunately not reported
> on the gitlab issue.) Any ideas, before I go on and resurrect this patch
> adding different strides for i915 and xe?

That bisect doesn't make any real sense to me unless there's an existing
bug in the xe code where it fails to pin (and somehow the smaller stride
alignment makes it fail) but it still reports success to the caller. 

Unfortunately that code in xe is completely illegible due the scoped
guard mess. So it's darn near impossible to see with a visual inspection
where it might silently fail. I think someone will need to sprinkle
debugs all over that code to track what is happening to the pin count.

-- 
Ville Syrjälä
Intel