[PATCH 3/3] drm/radeon: enable bapm by default on desktop TN/RL boards

[Alex Deucher]

On Mon, Jun 23, 2014 at 12:57 PM, Lucas Stach <l.stach at pengutronix.de> wrote:
> Am Mittwoch, den 18.06.2014, 16:25 -0400 schrieb Alex Deucher:
>> bapm enabled the GPU and CPU to share TDP headroom.  It was
>> disabled by default since some laptops hung when it was enabled
>> in conjunction with dpm.  It seems to be stable on desktop
>> boards and fixes hangs on boot with dpm enabled on certain
>> boards, so enable it by default on desktop boards.
>>
> Do you have any idea on why it fails on mobile parts? If there is any
> hint I can retest on my failing laptop. It would be nice to be able to
> enbale this on the mobile parts, too.

The problem seems to be related to switching between battery and AC.
There is code in the driver to en/disable bapm on plug/unplug events,
but it only fixed it for some users.

Alex


>
> Regards,
> Lucas
>
>> bug:
>> https://bugs.freedesktop.org/show_bug.cgi?id=72921
>>
>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>> ---
>>  drivers/gpu/drm/radeon/trinity_dpm.c | 10 +++++++++-
>>  1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/radeon/trinity_dpm.c b/drivers/gpu/drm/radeon/trinity_dpm.c
>> index 2a2822c..20da6ff 100644
>> --- a/drivers/gpu/drm/radeon/trinity_dpm.c
>> +++ b/drivers/gpu/drm/radeon/trinity_dpm.c
>> @@ -1874,7 +1874,15 @@ int trinity_dpm_init(struct radeon_device *rdev)
>>       for (i = 0; i < SUMO_MAX_HARDWARE_POWERLEVELS; i++)
>>               pi->at[i] = TRINITY_AT_DFLT;
>>
>> -     pi->enable_bapm = false;
>> +     /* There are stability issues reported on latops with
>> +      * bapm installed when switching between AC and battery
>> +      * power.  At the same time, some desktop boards hang
>> +      * if it's not enabled and dpm is enabled.
>> +      */
>> +     if (rdev->flags & RADEON_IS_MOBILITY)
>> +             pi->enable_bapm = false;
>> +     else
>> +             pi->enable_bapm = true;
>>       pi->enable_nbps_policy = true;
>>       pi->enable_sclk_ds = true;
>>       pi->enable_gfx_power_gating = true;
>
> --
> Pengutronix e.K.             | Lucas Stach                 |
> Industrial Linux Solutions   | http://www.pengutronix.de/  |
>