drm/i915: Automatic i915_switch_context for legacy

During request construction, after pinning the context we know whether
or not we have to emit a context switch. So move this common operation
from every caller into i915_gem_request_alloc() itself.

v2: Always submit the request if we emitted some commands during request
construction, as typically it also involves changes in global state.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171120102002.22254-2-chris@chris-wilson.co.uk

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 12e734b29463..be98868115bf 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1592,6 +1592,10 @@ static int ring_request_alloc(struct drm_i915_gem_request *request)
         if (ret)
                 return ret;
 
+        ret = i915_switch_context(request);
+        if (ret)
+                return ret;
+
         request->reserved_space -= LEGACY_REQUEST_SIZE;
         return 0;
 }