<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-cite-prefix">On 14/05/2022 00:06, Jordan Justen wrote: </div> <blockquote type="cite" cite="mid:165247597144.852381.16262736277926454494@jljusten-skl"> <pre class="moz-quote-pre" wrap="">On 2022-05-13 05:31:00, Lionel Landwerlin wrote: </pre> <blockquote type="cite"> <pre class="moz-quote-pre" wrap="">On 02/05/2022 17:15, Ramalingam C wrote: </pre> <blockquote type="cite"> <pre class="moz-quote-pre" wrap="">Capture the impact of memory region preference list of the objects, on their memory residency and Flat-CCS capability. v2: Fix the Flat-CCS capability of an obj with {lmem, smem} preference list [Thomas] v3: Reworded the doc [Matt] Signed-off-by: Ramalingam C <a class="moz-txt-link-rfc2396E" href="mailto:ramalingam.c@intel.com"><ramalingam.c@intel.com></a> cc: Matthew Auld <a class="moz-txt-link-rfc2396E" href="mailto:matthew.auld@intel.com"><matthew.auld@intel.com></a> cc: Thomas Hellstrom <a class="moz-txt-link-rfc2396E" href="mailto:thomas.hellstrom@linux.intel.com"><thomas.hellstrom@linux.intel.com></a> cc: Daniel Vetter <a class="moz-txt-link-rfc2396E" href="mailto:daniel.vetter@ffwll.ch"><daniel.vetter@ffwll.ch></a> cc: Jon Bloomfield <a class="moz-txt-link-rfc2396E" href="mailto:jon.bloomfield@intel.com"><jon.bloomfield@intel.com></a> cc: Lionel Landwerlin <a class="moz-txt-link-rfc2396E" href="mailto:lionel.g.landwerlin@intel.com"><lionel.g.landwerlin@intel.com></a> cc: Kenneth Graunke <a class="moz-txt-link-rfc2396E" href="mailto:kenneth@whitecape.org"><kenneth@whitecape.org></a> cc: <a class="moz-txt-link-abbreviated" href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> cc: Jordan Justen <a class="moz-txt-link-rfc2396E" href="mailto:jordan.l.justen@intel.com"><jordan.l.justen@intel.com></a> cc: Tony Ye <a class="moz-txt-link-rfc2396E" href="mailto:tony.ye@intel.com"><tony.ye@intel.com></a> Reviewed-by: Matthew Auld <a class="moz-txt-link-rfc2396E" href="mailto:matthew.auld@intel.com"><matthew.auld@intel.com></a> --- include/uapi/drm/i915_drm.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index a2def7b27009..b7e1c2fe08dc 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -3443,6 +3443,22 @@ struct drm_i915_gem_create_ext { * At which point we get the object handle in &drm_i915_gem_create_ext.handle, * along with the final object size in &drm_i915_gem_create_ext.size, which * should account for any rounding up, if required. + * + * Note that userspace has no means of knowing the current backing region + * for objects where @num_regions is larger than one. The kernel will only + * ensure that the priority order of the @regions array is honoured, either + * when initially placing the object, or when moving memory around due to + * memory pressure + * + * On Flat-CCS capable HW, compression is supported for the objects residing + * in I915_MEMORY_CLASS_DEVICE. When such objects (compressed) has other + * memory class in @regions and migrated (by I915, due to memory + * constrain) to the non I915_MEMORY_CLASS_DEVICE region, then I915 needs to + * decompress the content. But I915 dosen't have the required information to + * decompress the userspace compressed objects. + * + * So I915 supports Flat-CCS, only on the objects which can reside only on + * I915_MEMORY_CLASS_DEVICE regions. </pre> </blockquote> <pre class="moz-quote-pre" wrap=""> I think it's fine to assume Flat-CSS surface will always be in lmem. I see no issue for the Anv Vulkan driver. Maybe Nanley or Ken can speak for the Iris GL driver? </pre> </blockquote> <pre class="moz-quote-pre" wrap=""> Acked-by: Jordan Justen <a class="moz-txt-link-rfc2396E" href="mailto:jordan.l.justen@intel.com"><jordan.l.justen@intel.com></a> I think Nanley has accounted for this on iris with: <a class="moz-txt-link-freetext" href="https://gitlab.freedesktop.org/mesa/mesa/-/commit/42a865730ef72574e179b56a314f30fdccc6cba8">https://gitlab.freedesktop.org/mesa/mesa/-/commit/42a865730ef72574e179b56a314f30fdccc6cba8</a> -Jordan </pre> </blockquote> Thanks Jordan, We might want to through in an additional : assert((<code>flags &</code><code> BO_ALLOC_SMEM) == 0); in the CCS case </code> <code> </code> <code>-Lionel </code> </body> </html>