From 7f1ea2ac30171d9a6aad2916a73e41fa68c8f137 Mon Sep 17 00:00:00 2001
From: Michel Thierry <michel.thierry@intel.com>
Date: Tue, 30 May 2017 17:05:46 -0700
Subject: [PATCH] drm/i915/guc: Fix doorbell id selection
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>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170531000546.30762-1-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 e6e0c6ef1084..48a1e9349a2c 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;
--
2.50.1