[PATCH] drm/i915/guc: Fix doorbell id selection

* [PATCH] drm/i915/guc: Fix doorbell id selection
@ 2017-05-31  0:05 Michel Thierry
  2017-05-31  0:19 ` Daniele Ceraolo Spurio
  2017-05-31  0:21 ` ✓ Fi.CI.BAT: success for " Patchwork
  0 siblings, 2 replies; 5+ messages in thread
From: Michel Thierry @ 2017-05-31  0:05 UTC (permalink / raw)
  To: intel-gfx

We are passing parameters in the wrong order to find next zero bit, and
when it doesn't find anything it returns size (offset in the code), which
is always zero.

For reference the function is defined as:
find_next_bit( *addr, size, offset )

The incorrect parameter order was added by commit abddffdf3620e
("drm/i915/guc: Sanitize GuC client initialization"). Luckily, currently
we only use a single guc client and a single doorbell, which happens to be
zero; therefore it isn't necessary to backport this fix (which would be for
v4.12).

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index fb936bb5cb93..ec391ef981aa 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -105,7 +105,7 @@ static int __reserve_doorbell(struct i915_guc_client *client)
 		end += offset;
 	}
 
-	id = find_next_zero_bit(client->guc->doorbell_bitmap, offset, end);
+	id = find_next_zero_bit(client->guc->doorbell_bitmap, end, offset);
 	if (id == end)
 		return -ENOSPC;
 
-- 
2.11.0

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