[Intel-gfx] [PATCH] drm/i915/dmc: Use RUNTIME_INFO->stp for DMC

[Lucas De Marchi]

On Wed, Jun 30, 2021 at 05:15:00PM -0700, Jose Souza wrote:
>On Wed, 2021-06-30 at 17:01 -0700, Lucas De Marchi wrote:
>> Typo: RUNTIME_INFO->stp
>>
>> On Wed, Jun 30, 2021 at 04:06:24PM -0700, Anusha Srivatsa wrote:
>> > On the dmc side,we maintain a lookup table with different display
>> > stepping-substepping combinations.
>> >
>> > Instead of adding new table for every new platform, lets ues
>> > the stepping info from RUNTIME_INFO(dev_priv)->step
>> > Adding the helper intel_get_display_step().
>> >
>> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>> > Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
>> > ---
>> > drivers/gpu/drm/i915/display/intel_dmc.c | 49 ++++++++++++++++++++++--
>> > 1 file changed, 45 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
>> > index f8789d4543bf..c7ff7ff3f412 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dmc.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_dmc.c
>> > @@ -266,14 +266,55 @@ static const struct stepping_info icl_stepping_info[] = {
>> > };
>> >
>> > static const struct stepping_info no_stepping_info = { '*', '*' };
>> > +struct stepping_info *display_step;
>> > +
>> > +static struct stepping_info *
>> > +intel_get_display_stepping(struct intel_step_info step)
>> > +{
>> > +
>> > +	switch (step.display_step) {
>> > +	case STEP_A0:
>> > +		display_step->stepping = 'A';
>> > +		display_step->substepping = '0';
>> > +		break;
>> > +	case STEP_A2:
>> > +		display_step->stepping = 'A';
>> > +		display_step->substepping = '2';
>> > +		break;
>> > +	case STEP_B0:
>> > +		display_step->stepping = 'B';
>> > +		display_step->substepping = '0';
>> > +		break;
>> > +	case STEP_B1:
>> > +		display_step->stepping = 'B';
>> > +		display_step->substepping = '1';
>> > +		break;
>> > +	case STEP_C0:
>> > +		display_step->stepping = 'C';
>> > +		display_step->substepping = '0';
>> > +		break;
>> > +	case STEP_D0:
>> > +		display_step->stepping = 'D';
>> > +		display_step->substepping = '0';
>> > +		break;
>> > +	default:
>> > +		display_step->stepping = '*';
>> > +		display_step->substepping = '*';
>> > +		break;
>> > +	}
>>
>>
>> "crazy" idea that would avoid this type of conversion:
>> changing the step enum to be:
>>
>>
>> #define make_step(letter, num) (int)(((letter) << 8 ) | (num))
>>
>> STEP_A0 = make_step('A', '0'),
>> STEP_A1 = make_step('A', '1'),
>
>Looks a good idea to me, we could also keep it u8 using 4bits for each if there is memory concerns.

humn... indeed. Not much a concern actually, but not having to change
additional code is already a good thing.


I hope no stepping goes beyond Z9 :)

Lucas De Marchi

>
>>
>> and adapt the rest of the code to play with u16 instead of u8, and
>> handle the STEP_FUTURE/STEP_NONE/STEP_FOREVER.
>> Maybe it is crazy, dunno.
>>
>> +Jani / +Jose. Thoughts?
>>
>>
>> For this version the next comment is probably more important.
>>
>> > +	return display_step;
>> > +}
>> >
>> > static const struct stepping_info *
>> > intel_get_stepping_info(struct drm_i915_private *dev_priv)
>> > {
>> > 	const struct stepping_info *si;
>> > +	struct intel_step_info step = RUNTIME_INFO(dev_priv)->step;
>> > 	unsigned int size;
>> >
>> > -	if (IS_ICELAKE(dev_priv)) {
>> > +	if (DISPLAY_VER(dev_priv) >= 12) {
>> > +		si = intel_get_display_stepping(step);
>> > +	} else if (IS_ICELAKE(dev_priv)) {
>> > 		size = ARRAY_SIZE(icl_stepping_info);
>> > 		si = icl_stepping_info;
>>
>> can we move the other ones too? Just use display_step for all platforms.
>> Notice that before the separation we will have display_step ==
>> graphics_step, so it should just work.
>>
>>
>> Lucas De Marchi
>>
>> > 	} else if (IS_SKYLAKE(dev_priv)) {
>> > @@ -287,10 +328,10 @@ intel_get_stepping_info(struct drm_i915_private *dev_priv)
>> > 		si = NULL;
>> > 	}
>> >
>> > -	if (INTEL_REVID(dev_priv) < size)
>> > -		return si + INTEL_REVID(dev_priv);
>> > +	if (DISPLAY_VER(dev_priv) < 12)
>> > +		return INTEL_REVID(dev_priv) < size ? si + INTEL_REVID(dev_priv) : &no_stepping_info;
>> >
>> > -	return &no_stepping_info;
>> > +	return si;
>> > }
>> >
>> > static void gen9_set_dc_state_debugmask(struct drm_i915_private *dev_priv)
>> > --
>> > 2.32.0
>> >
>