drm/i915: Treat ringbuffer writes as write to normal memory
Ringbuffers are now being written to either through LLC or WC paths, so
treating them as simply iomem is no longer adequate. However, for the
older !llc hardware, the hardware is documentated as treating the TAIL
register update as serialising, so we can relax the barriers when filling
the rings (but even if it were not, it is still an uncached register write
and so serialising anyway.).
For simplicity, let's ignore the iomem annotation.
v2: Remove iomem from ringbuffer->virtual_address
v3: And for good measure add iomem elsewhere to keep sparse happy
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> #v2
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-8-git-send-email-chris@chris-wilson.co.uk
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-7-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c8ed367..093bfe1 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2860,6 +2860,7 @@
semaphore_waits_for(struct intel_engine_cs *engine, u32 *seqno)
{
struct drm_i915_private *dev_priv = engine->i915;
+ void __iomem *vaddr;
u32 cmd, ipehr, head;
u64 offset = 0;
int i, backwards;
@@ -2898,6 +2899,7 @@
*/
head = I915_READ_HEAD(engine) & HEAD_ADDR;
backwards = (INTEL_GEN(dev_priv) >= 8) ? 5 : 4;
+ vaddr = (void __iomem *)engine->buffer->virtual_start;
for (i = backwards; i; --i) {
/*
@@ -2908,7 +2910,7 @@
head &= engine->buffer->size - 1;
/* This here seems to blow up */
- cmd = ioread32(engine->buffer->virtual_start + head);
+ cmd = ioread32(vaddr + head);
if (cmd == ipehr)
break;
@@ -2918,11 +2920,11 @@
if (!i)
return NULL;
- *seqno = ioread32(engine->buffer->virtual_start + head + 4) + 1;
+ *seqno = ioread32(vaddr + head + 4) + 1;
if (INTEL_GEN(dev_priv) >= 8) {
- offset = ioread32(engine->buffer->virtual_start + head + 12);
+ offset = ioread32(vaddr + head + 12);
offset <<= 32;
- offset = ioread32(engine->buffer->virtual_start + head + 8);
+ offset |= ioread32(vaddr + head + 8);
}
return semaphore_wait_to_signaller_ring(engine, ipehr, offset);
}