From df0700e53047662c167836bd6fdeea55d5d8dcfa Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 6 Sep 2017 20:24:24 +0100
Subject: [PATCH] drm/i915: Disable snooping (userptr, set-cache-level) on gen4
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Git-commit: df0700e53047662c167836bd6fdeea55d5d8dcfa
Patch-mainline: v4.15-rc1
References: FATE#322643 bsc#1055900
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@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170906192424.26970-1-chris@chris-wilson.co.uk
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/i915_pci.c | 2 ++
drivers/gpu/drm/i915/intel_device_info.c | 2 --
2 files changed, 2 insertions(+), 2 deletions(-)
--- 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 in
.platform = INTEL_I965G,
.has_overlay = 1,
.hws_needs_physical = 1,
+ .has_snoop = false,
};
static const struct intel_device_info intel_i965gm_info = {
@@ -177,6 +178,7 @@ static const struct intel_device_info in
.has_overlay = 1,
.supports_tv = 1,
.hws_needs_physical = 1,
+ .has_snoop = false,
};
static const struct intel_device_info intel_g45_info = {
--- 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(stru
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",