drm/radeon/kms: enable ACPI powermanagement mode on radeon gpus.

Some GPUs have an APM/ACPI PM mode selection switch and some BIOSes
set this to APM. We really want this in ACPI mode for Linux.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index c8f4b0300b70..3ae51ada1abf 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -1809,6 +1809,7 @@ void r100_set_common_regs(struct radeon_device *rdev)
 {
         struct drm_device *dev = rdev->ddev;
         bool force_dac2 = false;
+        u32 tmp;
 
         /* set these so they don't interfere with anything */
         WREG32(RADEON_OV0_SCALE_CNTL, 0);
@@ -1880,6 +1881,12 @@ void r100_set_common_regs(struct radeon_device *rdev)
                 WREG32(RADEON_DISP_HW_DEBUG, disp_hw_debug);
                 WREG32(RADEON_DAC_CNTL2, dac2_cntl);
         }
+
+        /* switch PM block to ACPI mode */
+        tmp = RREG32_PLL(RADEON_PLL_PWRMGT_CNTL);
+        tmp &= ~RADEON_PM_MODE_SEL;
+        WREG32_PLL(RADEON_PLL_PWRMGT_CNTL, tmp);
+
 }
 
 /*