Re: [Intel-gfx] [PATCH 01/53] drm/i915: Add "release id" version

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 02 Jul 2021, Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> wrote:
> On 01/07/2021 21:23, Matt Roper wrote:
>> From: Lucas De Marchi <lucas.demarchi@intel.com>
>> 
>> Besides the arch version returned by GRAPHICS_VER(), new platforms
>> contain a "release id" to make clear the difference from one platform to
>> another. Although for the first ones we may use them as if they were a
>
> What does "first ones" refer to here?
>
>> major/minor version, that is not true for all platforms: we may have a
>> `release_id == n` that is closer to `n - 2` than to `n - 1`.
>
> Hm this is a bit confusing. Is the sentence simply trying to say that, 
> as the release id number is growing, hw capabilities are not simply 
> accumulating but can be removed as well? Otherwise I am not sure how the 
> user of these macros is supposed to act on this sentence.
>
>> However the release id number is not defined by hardware until we start
>> using the GMD_ID register. For the platforms before that register is
>> useful we will set the values in software and we can set them as we
>> please. So the plan is to set them so we can group different features
>> under a single GRAPHICS_VER_FULL() check.
>> 
>> After GMD_ID is used, the usefulness of a "full version check" will be
>> greatly reduced and will be mostly used for deciding workarounds and a
>> few code paths. So it makes sense to keep it as a separate field from
>> graphics_ver.
>> 
>> Also, currently there is not much use for the release id in media and
>> display, so keep them out.
>> 
>> This is a mix of 2 independent changes: one by me and the other by Matt
>> Roper.
>> 
>> Cc: Matt Roper <matthew.d.roper@intel.com>
>> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
>> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_drv.h          | 6 ++++++
>>   drivers/gpu/drm/i915/intel_device_info.c | 2 ++
>>   drivers/gpu/drm/i915/intel_device_info.h | 2 ++
>>   3 files changed, 10 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 6dff4ca01241..9639800485b9 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -1258,11 +1258,17 @@ static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
>>    */
>>   #define IS_GEN(dev_priv, n)		(GRAPHICS_VER(dev_priv) == (n))
>>   
>> +#define IP_VER(ver, release)		((ver) << 8 | (release))
>> +
>>   #define GRAPHICS_VER(i915)		(INTEL_INFO(i915)->graphics_ver)
>> +#define GRAPHICS_VER_FULL(i915)		IP_VER(INTEL_INFO(i915)->graphics_ver, \
>> +					       INTEL_INFO(i915)->graphics_ver_release)
>>   #define IS_GRAPHICS_VER(i915, from, until) \
>>   	(GRAPHICS_VER(i915) >= (from) && GRAPHICS_VER(i915) <= (until))
>>   
>>   #define MEDIA_VER(i915)			(INTEL_INFO(i915)->media_ver)
>> +#define MEDIA_VER_FULL(i915)		IP_VER(INTEL_INFO(i915)->media_ver, \
>> +					       INTEL_INFO(i915)->media_ver_release)
>>   #define IS_MEDIA_VER(i915, from, until) \
>>   	(MEDIA_VER(i915) >= (from) && MEDIA_VER(i915) <= (until))
>>   
>> diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
>> index 7eaa92fee421..e8ad14f002c1 100644
>> --- a/drivers/gpu/drm/i915/intel_device_info.c
>> +++ b/drivers/gpu/drm/i915/intel_device_info.c
>> @@ -97,7 +97,9 @@ void intel_device_info_print_static(const struct intel_device_info *info,
>>   				    struct drm_printer *p)
>>   {
>>   	drm_printf(p, "graphics_ver: %u\n", info->graphics_ver);
>> +	drm_printf(p, "graphics_ver_release: %u\n", info->graphics_ver_release);
>
> I get the VER and VER_FULL in the macros but could 'ver' and 
> 'ver_release' here and in the code simply be renamed to 'ver'/'version' 
> and 'release'? Maybe it is just me but don't think I encountered the 
> term "version release" before.

Just bikeshedding here, but I thought of:

	if (info->grapics_ver_release)
		drm_printf(p, "graphics_ver: %u.%u\n", info->graphics_ver, info->graphics_ver_release);
	else
		drm_printf(p, "graphics_ver: %u\n", info->graphics_ver);

Also, I thought "x_ver" and "x_ver_release" sounds a bit odd, perhaps
having "x_ver" and "x_rel" is more natural?

Ultimately I think we've historically always sucked at trying to figure
this out up front, so maybe the right answer is merging something and
fixing later...


BR,
Jani.





>
> Regards,
>
> Tvrtko
>
>>   	drm_printf(p, "media_ver: %u\n", info->media_ver);
>> +	drm_printf(p, "media_ver_release: %u\n", info->media_ver_release);
>>   	drm_printf(p, "display_ver: %u\n", info->display.ver);
>>   	drm_printf(p, "gt: %d\n", info->gt);
>>   	drm_printf(p, "iommu: %s\n", iommu_name());
>> diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
>> index b326aff65cd6..944a5ff4df49 100644
>> --- a/drivers/gpu/drm/i915/intel_device_info.h
>> +++ b/drivers/gpu/drm/i915/intel_device_info.h
>> @@ -162,7 +162,9 @@ enum intel_ppgtt_type {
>>   
>>   struct intel_device_info {
>>   	u8 graphics_ver;
>> +	u8 graphics_ver_release;
>>   	u8 media_ver;
>> +	u8 media_ver_release;
>>   
>>   	u8 gt; /* GT number, 0 if undefined */
>>   	intel_engine_mask_t platform_engine_mask; /* Engines supported by the HW */
>> 

-- 
Jani Nikula, Intel Open Source Graphics Center
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