Quoting Luca Coelho (2024-11-01 09:24:08-03:00)
>On Mon, 2024-10-21 at 19:27 -0300, Gustavo Sousa wrote:
>> Bspec says that disabling dynamic DC states require taking the DMC
>> wakelock to cause an DC exit before writing to DC_STATE_EN. Implement
>> that.
>>
>> In fact, testing on PTL revealed we end up failing to exit DC5/6 without
>> this step.
>>
>> Bspec: 71583
>> Signed-off-by: Gustavo Sousa <gustavo.sousa@xxxxxxxxx>
>> ---
>> .../drm/i915/display/intel_display_power_well.c | 10 +++++++---
>> drivers/gpu/drm/i915/display/intel_dmc_wl.c | 14 ++++++++++++--
>> drivers/gpu/drm/i915/display/intel_dmc_wl.h | 2 ++
>> 3 files changed, 21 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_power_well.c b/drivers/gpu/drm/i915/display/intel_display_power_well.c
>> index adaf7cf3a33b..e8946ce86aaa 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_power_well.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display_power_well.c
>> @@ -987,10 +987,14 @@ void gen9_disable_dc_states(struct intel_display *display)
>> return;
>> }
>>
>> - gen9_set_dc_state(display, DC_STATE_DISABLE);
>> -
>> - if (!HAS_DISPLAY(display))
>> + if (HAS_DISPLAY(display)) {
>> + intel_dmc_wl_get_noreg(display);
>> + gen9_set_dc_state(display, DC_STATE_DISABLE);
>> + intel_dmc_wl_put_noreg(display);
>> + } else {
>> + gen9_set_dc_state(display, DC_STATE_DISABLE);
>> return;
>> + }
>
>I think intel_dmc_get/put() already protect indirectly on
>HAS_DISPLAY(), doesn't it? If that's the case, then the if here is
>unnecessary.
Actually, intel_dmc_wl_init() gets called only when HAS_DISPLAY() is
true, so I think using intel_dmc_wl_{get,put}_noreg() for the
!HAS_DISPLAY() case would not be right, at least not with the current
state of the code.
--
Gustavo Sousa
