[PATCH] drm/amdgpu: Fix num_doorbell calculation issue

[Oak Zeng]

When paging queue is enabled, it use the second page of doorbell.
The AMDGPU_DOORBELL64_MAX_ASSIGNMENT definition assumes all the
kernel doorbells are in the first page. So with paging queue enabled,
the total kernel doorbell range should be original num_doorbell plus
one page (0x400 in dword), not *2.

Change-Id: I62023bb91da33ca5532b22b263771b587b796d59
Signed-off-by: Oak Zeng <ozeng at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 8eaa40e..c75badf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -539,10 +539,13 @@ static int amdgpu_device_doorbell_init(struct amdgpu_device *adev)
 		return -EINVAL;
 
 	/* For Vega, reserve and map two pages on doorbell BAR since SDMA
-	 * paging queue doorbell use the second page
+	 * paging queue doorbell use the second page. The
+	 * AMDGPU_DOORBELL64_MAX_ASSIGNMENT definition assumes all the
+	 * doorbells are in the first page. So with paging queue enabled,
+	 * the max num_doorbells should + 1 page (0x400 in dword)
 	 */
 	if (adev->asic_type >= CHIP_VEGA10)
-		adev->doorbell.num_doorbells *= 2;
+		adev->doorbell.num_doorbells += 0x400;
 
 	adev->doorbell.ptr = ioremap(adev->doorbell.base,
 				     adev->doorbell.num_doorbells *
-- 
2.7.4