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

[Lucas De Marchi]

On Fri, Jul 02, 2021 at 10:49:05AM +0300, Jani Nikula wrote:
>On Wed, 30 Jun 2021, Lucas De Marchi <lucas.demarchi at intel.com> 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'),
>>
>> 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?
>
>Frankly, I think all of this should be incorporated to intel_step.[ch]
>instead of having a semi-overlapping handling here. Just look at the
>amount of duplication already.

I guess you missed I gave the same suggestion below and that there is
already a new version of this patch? Question here was about going a
step further to avoid the conversion STEP_* to 2 chars.

thanks
Lucas De Marchi

>
>
>BR,
>Jani.
>
>>
>>
>> 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
>>>
>
>-- 
>Jani Nikula, Intel Open Source Graphics Center