drm/amdgpu: adjust default dispclk (v2)

Set the default to 600Mhz if it's not set in the bios,
and bump the default to 600Mhz if it's lower than that.

Port of radeon commit:
9368931db826d57b6b88b3145a00276626b48df0

v2: clean up the code a bit

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=91896

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
index 77f1d7c6ea3af627324b147e63b21b6cbdd16302..9416e0f5c1db2bf8c5601ddee999b1ade5efabc0 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
@@ -672,8 +672,12 @@ int amdgpu_atombios_get_clock_info(struct amdgpu_device *adev)
                /* disp clock */
                adev->clock.default_dispclk =
                        le32_to_cpu(firmware_info->info_21.ulDefaultDispEngineClkFreq);
-               if (adev->clock.default_dispclk == 0)
-                       adev->clock.default_dispclk = 54000; /* 540 Mhz */
+               /* set a reasonable default for DP */
+               if (adev->clock.default_dispclk < 53900) {
+                       DRM_INFO("Changing default dispclk from %dMhz to 600Mhz\n",
+                                adev->clock.default_dispclk / 100);
+                       adev->clock.default_dispclk = 60000;
+               }
                adev->clock.dp_extclk =
                        le16_to_cpu(firmware_info->info_21.usUniphyDPModeExtClkFreq);
                adev->clock.current_dispclk = adev->clock.default_dispclk;