[PATCH RFC] drm/atomic: Fall back to legacy call back in *_connector_dpms()

Tomi Valkeinen tomi.valkeinen at ti.com
Fri Feb 12 17:08:46 UTC 2016


On 12/02/16 17:34, Daniel Vetter wrote:
> On Fri, Feb 12, 2016 at 05:17:19PM +0200, Jyri Sarha wrote:
>> Fall back to legacy drm_helper_connector_dpms() call back in
>> drm_atomic_helper_connector_dpms() if DRIVER_ATOMIC feature is not
>> present.
>>
>> Calling drm_atomic_helper_connector_dpms() from non atomic driver
>> causes undefined behavior. This is a problem with componentized
>> encoder/connector drivers that may be bound to both atomic and
>> non atomic drivers.
>>
>> Signed-off-by: Jyri Sarha <jsarha at ti.com>
>> ---
>> This is just an alternative to this:
>> https://lists.freedesktop.org/archives/dri-devel/2016-January/098867.html
> 
> I like the linked patch much better, since non-atomic really should die.
> Inflicting non-atomic on atomic helpers is bad imo, so nack from me on
> this patch here.

I mostly agree, but we are in a transition period from non-atomic to
atomic. When all drivers have been converted to atomic, it should be
easy to grep for code using DRIVER_ATOMIC (or similar), and remove all
the non-atomic support code.

In my opinion it should be considered case by case if the
non-atomic/atomic compat code should be added to the generic functions
or to all the drivers using that functionality.

In this case, if it only affects tda998x (but does it?), perhaps the
patch in the link is better.

 Tomi

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