From: Xiangliang Yu <Xiangliang.Yu@amd.com>
Date: Fri, 9 Jun 2017 17:12:02 +0800
Subject: drm/amdgpu: reduce the time of reading VBIOS
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Git-commit: f31c94d1de618064d5212462363f570a42ab39df
Patch-mainline: v4.14-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

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>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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(stru
 
 	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;
 	}