From 3e2926f8753dac1ded56c8ef3e91f56ee763dafd Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Fri, 4 Jun 2021 09:00:11 -0400 Subject: drm/panfrost: Add AFBC_FEATURES parameter The value of the AFBC_FEATURES register is required by userspace to determine AFBC support on Bifrost. A user on our IRC channel (#panfrost) reported a workload that raised a fault on one system's Mali G31 but worked flawlessly with another system's Mali G31. We determined the cause to be missing AFBC support on one vendor's Mali implementation -- it turns out AFBC is optional on Bifrost! Whether AFBC is supported or not is exposed in the AFBC_FEATURES register on Bifrost, which reads back as 0 on Midgard. A zero value indicates AFBC is fully supported, provided the architecture itself supports AFBC, allowing backwards-compatibility with Midgard. Bits 0 and 15 indicate that AFBC support is absent for texturing and rendering respectively. The user experiencing the fault reports that AFBC_FEATURES reads back 0x10001 on their system, confirming the architectural lack of AFBC. Userspace needs this parameter to know to disable AFBC on that chip, and perhaps others. v2: Fix typo from copy-paste fail. v3: Bump the UABI version. This commit was cherry-picked from another series so chalking this up to a rebase fail. Signed-off-by: Alyssa Rosenzweig Reviewed-by: Steven Price Cc: Rob Herring Cc: Tomeu Vizoso Signed-off-by: Steven Price Link: https://patchwork.freedesktop.org/patch/msgid/20210604130011.3203-1-alyssa.rosenzweig@collabora.com --- include/uapi/drm/panfrost_drm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/drm/panfrost_drm.h') diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h index ec19db1eead8..061e700dd06c 100644 --- a/include/uapi/drm/panfrost_drm.h +++ b/include/uapi/drm/panfrost_drm.h @@ -171,6 +171,7 @@ enum drm_panfrost_param { DRM_PANFROST_PARAM_JS_FEATURES15, DRM_PANFROST_PARAM_NR_CORE_GROUPS, DRM_PANFROST_PARAM_THREAD_TLS_ALLOC, + DRM_PANFROST_PARAM_AFBC_FEATURES, }; struct drm_panfrost_get_param { -- cgit