From: Alex Deucher <alexander.deucher@amd.com>
Date: Fri, 30 Jun 2017 17:26:47 -0400
Subject: drm/amdgpu: check scratch registers to see if we need post (v2)
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Git-commit: 70d17a25da21e1d497db3580ae27682952ddfd98
Patch-mainline: v4.14-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Rather than checking the CONGIG_MEMSIZE register as that may
not be reliable on some APUs.

v2: The scratch register is only used on CIK+

Reviewed-by: Junwei Zhang <Jerry.Zhang@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_device.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -736,7 +736,12 @@ bool amdgpu_need_post(struct amdgpu_devi
 		adev->has_hw_reset = false;
 		return true;
 	}
-	/* then check MEM_SIZE, in case the crtcs are off */
+
+	/* bios scratch used on CIK+ */
+	if (adev->asic_type >= CHIP_BONAIRE)
+		return amdgpu_atombios_scratch_need_asic_init(adev);
+
+	/* check MEM_SIZE for older asics */
 	reg = amdgpu_asic_get_config_memsize(adev);
 
 	if ((reg != 0) && (reg != 0xffffffff))