drm/amdgpu: reduce the time of reading VBIOS

VRAM is usually marked write combined, so change ioremap mode from
noncache to write combine for reading vbios from VRAM.

This will reduce cost time of reading vbios from 188ms to 8ms.

Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
index ea3a2501c7cd4e8d04e54d8963b7401a010e7f2a..c21adf60a7f200ba6a4faaa32c163157d00da9ce 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
@@ -104,7 +104,7 @@ static bool igp_read_bios_from_vram(struct amdgpu_device *adev)
 
        adev->bios = NULL;
        vram_base = pci_resource_start(adev->pdev, 0);
-       bios = ioremap(vram_base, size);
+       bios = ioremap_wc(vram_base, size);
        if (!bios) {
                return false;
        }