Comment # 7
on bug 66963
from Sergey
Some findings:
The actual hand happens in
drivers/gpu/drm/radeon/rv6xx_dpm.c:
int rv6xx_dpm_enable(struct radeon_device *rdev)
on 'r600_start_dpm(rdev)' call.
Makes sense that configurations are harmless before actual dpm is enabled.
>>From this function it looks like we disable sclk and mclk do pll configuration,
then enable clocks back. But even if I leave:
void r600_start_dpm(struct radeon_device *rdev)
{
r600_enable_sclk_control(rdev, false);
r600_enable_mclk_control(rdev, false);
r600_enable_sclk_control(rdev, true);
r600_enable_mclk_control(rdev, true);
}
System still fails with black screen.
There is also peace of code in r600_start_dpm() that is duplicated:
r600_enable_spll_bypass(rdev, true);
r600_wait_for_spll_change(rdev);
r600_enable_spll_bypass(rdev, false);
r600_wait_for_spll_change(rdev);
r600_enable_spll_bypass(rdev, true);
r600_wait_for_spll_change(rdev);
r600_enable_spll_bypass(rdev, false);
r600_wait_for_spll_change(rdev);
(probably this intentional, just checking)
Sorry if it doesn't make any sense, I'm new with radeon driver and don't know
how 'dpm' is supposed to work for this HW.