From: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Date: Sat, 2 Jun 2018 12:29:45 +0100
Subject: drm/i915: drop one bit on the hw_id when using guc
Git-commit: 218b5000982b7c5e7433b86819be92f95984a1ae
Patch-mainline: v4.19-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
We currently using GuC as a proxy to the hardware. When Guc is used in
such mode, it consumes the bit 20 of the hw_id to indicate that the
workload was submitted by proxy.
So far we probably haven't seen the issue because we need to allocate
1048576+ contexts to hit this issue. Still, we should avoid allocating
the hw_id on that bit and restriction to bits [0:19] (i.e 20bits
instead of 21).
v2: Leave the max hw_id computation in i915_gem_context.c (Michel)
v3: Be consistent on if/else usage (Chris)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
BSpec: 1237
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180602112946.30803-2-lionel.g.landwerlin@intel.com
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem_context.c | 15 ++++++++++++---
drivers/gpu/drm/i915/intel_lrc.c | 2 +-
3 files changed, 14 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1849,6 +1849,7 @@ struct drm_i915_private {
*/
struct ida hw_ida;
#define MAX_CONTEXT_HW_ID (1<<21) /* exclusive */
+#define MAX_GUC_CONTEXT_HW_ID (1 << 20) /* exclusive */
#define GEN11_MAX_CONTEXT_HW_ID (1<<11) /* exclusive */
} contexts;
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -208,10 +208,19 @@ static int assign_hw_id(struct drm_i915_
int ret;
unsigned int max;
- if (INTEL_GEN(dev_priv) >= 11)
+ if (INTEL_GEN(dev_priv) >= 11) {
max = GEN11_MAX_CONTEXT_HW_ID;
- else
- max = MAX_CONTEXT_HW_ID;
+ } else {
+ /*
+ * When using GuC in proxy submission, GuC consumes the
+ * highest bit in the context id to indicate proxy submission.
+ */
+ if (USES_GUC_SUBMISSION(dev_priv))
+ max = MAX_GUC_CONTEXT_HW_ID;
+ else
+ max = MAX_CONTEXT_HW_ID;
+ }
+
ret = ida_simple_get(&dev_priv->contexts.hw_ida,
0, max, GFP_KERNEL);
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -200,7 +200,7 @@ static inline bool need_preempt(const st
*
* bits 0-11: flags, GEN8_CTX_* (cached in ctx->desc_template)
* bits 12-31: LRCA, GTT address of (the HWSP of) this context
- * bits 32-52: ctx ID, a globally unique tag
+ * bits 32-52: ctx ID, a globally unique tag (highest bit used by GuC)
* bits 53-54: mbz, reserved for use by hardware
* bits 55-63: group ID, currently unused and set to 0
*