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

[Michel Thierry]

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 at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Oscar Mateo <oscar.mateo at intel.com>
Signed-off-by: Michel Thierry <michel.thierry at 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