Re: [PATCH i-g-t] lib/intel_pat: add hardcoded PAT fallback for older kernels

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Tue, 31 Mar 2026 15:56:57 -0700, Dixit, Ashutosh wrote:
>
> > @@ -105,14 +161,26 @@ static void intel_get_pat_idx(int fd, struct intel_pat_cache *pat)
> >	 * For Xe, use the PAT cache stored in struct xe_device.
> >	 * xe_device_get() populates the cache while still root; forked
> >	 * children that inherit the xe_device can use it post-drop_root().
> > +	 *
> > +	 * Fall back to hardcoded values when the kernel lacks the
> > +	 * pat_sw_config debugfs. Platforms newer than Crescent Island
> > +	 * must have the debugfs available.
> >	 */
> >	if (is_xe_device(fd)) {
> >		struct xe_device *xe_dev = xe_device_get(fd);
> >
> > -		igt_assert_f(xe_dev->pat_cache,
> > -			     "PAT sw_config not available -- "
> > -			     "debugfs not accessible (missing root or not mounted?)\n");
> > -		*pat = *xe_dev->pat_cache;
> > +		if (xe_dev->pat_cache) {
> > +			*pat = *xe_dev->pat_cache;
> > +		} else if (xe_pat_fallback(fd, pat)) {
>
> Shouldn't this be "else if (!xe_pat_fallback(fd, pat)"? Or return 0 from
> xe_pat_fallback() on success?

Sorry, misread the code, please ignore, code is correct!