On Wed, Sep 06, 2017 at 08:24:24PM +0100, Chris Wilson wrote:
> The original gen4 has an issue where writes (both render and blt) into
> snoopable pages are lost. We've previously worked around this in
> userspace (ddx, igt) by simply not requesting snoopable buffers, but upon
> rediscovering this problem for a third time, make the kernel reject such
> requests with -ENODEV.
>
> This disables snooping on userspace buffers for i965g and i965gm (original
> gen4) machines.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
(even if greg ignores it ...)
-Daniel
> ---
> drivers/gpu/drm/i915/i915_pci.c | 2 ++
> drivers/gpu/drm/i915/intel_device_info.c | 2 --
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> index 881b5d6708aa..e95baf3c4314 100644
> --- a/drivers/gpu/drm/i915/i915_pci.c
> +++ b/drivers/gpu/drm/i915/i915_pci.c
> @@ -168,6 +168,7 @@ static const struct intel_device_info intel_i965g_info __initconst = {
> .platform = INTEL_I965G,
> .has_overlay = 1,
> .hws_needs_physical = 1,
> + .has_snoop = false,
> };
>
> static const struct intel_device_info intel_i965gm_info __initconst = {
> @@ -177,6 +178,7 @@ static const struct intel_device_info intel_i965gm_info __initconst = {
> .has_overlay = 1,
> .supports_tv = 1,
> .hws_needs_physical = 1,
> + .has_snoop = false,
> };
>
> static const struct intel_device_info intel_g45_info __initconst = {
> diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
> index b17f7045c8f8..43831b09b47a 100644
> --- a/drivers/gpu/drm/i915/intel_device_info.c
> +++ b/drivers/gpu/drm/i915/intel_device_info.c
> @@ -412,8 +412,6 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
> else if (INTEL_INFO(dev_priv)->gen >= 9)
> gen9_sseu_info_init(dev_priv);
>
> - WARN_ON(info->has_snoop != !info->has_llc);
> -
> DRM_DEBUG_DRIVER("slice mask: %04x\n", info->sseu.slice_mask);
> DRM_DEBUG_DRIVER("slice total: %u\n", hweight8(info->sseu.slice_mask));
> DRM_DEBUG_DRIVER("subslice total: %u\n",
> --
> 2.14.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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