[PATCH v2] drm/dp: Add function to parse EDID descriptors for adaptive sync limits

Kazlauskas, Nicholas nicholas.kazlauskas at amd.com
Mon Mar 2 14:15:27 UTC 2020


On 2020-02-28 9:38 p.m., Manasi Navare wrote:
> On Fri, Feb 28, 2020 at 01:18:45PM -0800, Manasi Navare wrote:
>> On Thu, Jan 09, 2020 at 03:08:52PM +0200, Ville Syrjälä wrote:
>>> On Tue, Jan 07, 2020 at 04:32:08PM -0800, Manasi Navare wrote:
>>>> Adaptive Sync is a VESA feature so add a DRM core helper to parse
>>>> the EDID's detailed descritors to obtain the adaptive sync monitor range.
>>>> Store this info as part fo drm_display_info so it can be used
>>>> across all drivers.
>>>> This part of the code is stripped out of amdgpu's function
>>>> amdgpu_dm_update_freesync_caps() to make it generic and be used
>>>> across all DRM drivers
>>>>
>>>> v2:
>>>> * Change vmin and vmax to use u8 (Ville)
>>>> * Dont store pixel clock since that is just a max dotclock
>>>> and not related to VRR mode (Manasi)
>>>>
>>>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>> Cc: Harry Wentland <harry.wentland at amd.com>
>>>> Cc: Clinton A Taylor <clinton.a.taylor at intel.com>
>>>> Cc: Nicholas Kazlauskas <nicholas.kazluaskas at amd.com>
>>>> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>

Hi Manasi, sorry for the delayed response on this one!

Few comments inline below:

>>>> ---
>>>>   drivers/gpu/drm/drm_edid.c  | 51 +++++++++++++++++++++++++++++++++++++
>>>>   include/drm/drm_connector.h | 22 ++++++++++++++++
>>>>   include/drm/drm_edid.h      |  2 ++
>>>>   3 files changed, 75 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>>>> index 99769d6c9f84..52781a0e708b 100644
>>>> --- a/drivers/gpu/drm/drm_edid.c
>>>> +++ b/drivers/gpu/drm/drm_edid.c
>>>> @@ -4880,6 +4880,54 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
>>>>   	}
>>>>   }
>>>>   
>>>> +void drm_get_adaptive_sync_limits(struct drm_connector *connector,
>>>> +				  const struct edid *edid)

Agree with other feedback here on making this static. We can move over 
amdgpu to just check the DRM reported caps after.

>>>> +{
>>>> +	struct drm_display_info *info = &connector->display_info;
>>>> +	const struct detailed_timing *timing;
>>>> +	const struct detailed_non_pixel *data;
>>>> +	const struct detailed_data_monitor_range *range;
>>>
>>> Needlessly wide scope for everything above.
>>
>> Ok will add this inside the for loop
>>
>>>
>>>> +	int i;
>>>> +
>>>> +	/*
>>>> +	 * Restrict Adaptive Sync only for dp and edp
>>>> +	 */
>>>> +	if (connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort &&
>>>> +	    connector->connector_type != DRM_MODE_CONNECTOR_eDP)
>>>> +		return;

This probably doesn't need to be blocked here, this is just parsing the 
EDID.

>>>> +
>>>> +	if (edid->version <= 1 && !(edid->version == 1 && edid->revision > 1))
>>>> +		return;
>>>
>>> if (!version_greater(...))
>>> 	return;
>>>
>>>> +
>>>> +	for (i = 0; i < 4; i++) {
>>>
>>> This should probably use for_each_detailed_block()
>>
>> Can you elaborate, I dont understand what you mean by using for_each_detailed_block()
>>
>> Manasi
> 
> Does that mean:
> I need to define drm_edid_get_vrr_range()  where i call drm_for_each_detailed_block((u8 * )edid, get_vrr_range, &vrr_min, &vrr_max)  but i need to access range   = &data->data.range; where
>   data = &timing->data.other_data; inside get_vrr_range() how can I access range?
> 
> Manasi

Wouldn't it look like:

drm_for_each_detailed_block((u8 *)edid, get_adaptive_sync_range, 
&info->adaptive_sync);

Or something along those lines?

> 
>>
>>>
>>>> +		timing  = &edid->detailed_timings[i];
>>>> +		data    = &timing->data.other_data;
>>>> +		range   = &data->data.range;
>>>> +		/*
>>>> +		 * Check if monitor has continuous frequency mode
>>>> +		 */
>>>> +		if (data->type != EDID_DETAIL_MONITOR_RANGE)
>>>> +			continue;
>>>> +		/*
>>>> +		 * Check for flag range limits only. If flag == 1 then
>>>> +		 * no additional timing information provided.
>>>> +		 * Default GTF, GTF Secondary curve and CVT are not
>>>> +		 * supported
>>>> +		 */
>>>> +		if (range->flags != 1)
>>>> +			continue;
>>>> +
>>>> +		info->adaptive_sync.min_vfreq = range->min_vfreq;
>>>> +		info->adaptive_sync.max_vfreq = range->max_vfreq;
>>>> +
>>>> +		DRM_DEBUG_KMS("Adaptive Sync refresh rate range is %d Hz - %d Hz\n",
>>>> +			      info->adaptive_sync.min_vfreq,
>>>> +			      info->adaptive_sync.max_vfreq);
>>>> +		break;
>>>> +	}
>>>> +}
>>>> +EXPORT_SYMBOL(drm_get_adaptive_sync_limits);

Can drop this EXPORT since this is all in drm_edid.c.

>>>> +
>>>>   /* A connector has no EDID information, so we've got no EDID to compute quirks from. Reset
>>>>    * all of the values which would have been set from EDID
>>>>    */
>>>> @@ -4901,6 +4949,7 @@ drm_reset_display_info(struct drm_connector *connector)
>>>>   	memset(&info->hdmi, 0, sizeof(info->hdmi));
>>>>   
>>>>   	info->non_desktop = 0;
>>>> +	memset(&info->adaptive_sync, 0, sizeof(info->adaptive_sync));
>>>>   }
>>>>   
>>>>   u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edid)
>>>> @@ -4916,6 +4965,8 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
>>>>   
>>>>   	info->non_desktop = !!(quirks & EDID_QUIRK_NON_DESKTOP);
>>>>   
>>>> +	drm_get_adaptive_sync_limits(connector, edid);
>>>> +
>>>>   	DRM_DEBUG_KMS("non_desktop set to %d\n", info->non_desktop);
>>>>   
>>>>   	if (edid->revision < 3)
>>>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>>>> index 221910948b37..77df404a2e01 100644
>>>> --- a/include/drm/drm_connector.h
>>>> +++ b/include/drm/drm_connector.h
>>>> @@ -254,6 +254,23 @@ enum drm_panel_orientation {
>>>>   	DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,
>>>>   };
>>>>   
>>>> +/**
>>>> + * struct drm_adaptive_sync_info - Panel's Adaptive Sync capabilities for
>>>> + * &drm_display_info
>>>> + *
>>>> + * This struct is used to store a Panel's Adaptive Sync capabilities
>>>> + * as parsed from EDID's detailed monitor range descriptor block.
>>>> + *
>>>> + * @min_vfreq: This is the min supported refresh rate in Hz from
>>>> + *             EDID's detailed monitor range.
>>>> + * @max_vfreq: This is the max supported refresh rate in Hz from
>>>> + *             EDID's detailed monitor range
>>>> + */
>>>> +struct drm_adaptive_sync_info {
>>>> +	u8 min_vfreq;
>>>> +	u8 max_vfreq;
>>>> +};
>>>> +
>>>>   /*
>>>>    * This is a consolidated colorimetry list supported by HDMI and
>>>>    * DP protocol standard. The respective connectors will register
>>>> @@ -465,6 +482,11 @@ struct drm_display_info {
>>>>   	 * @non_desktop: Non desktop display (HMD).
>>>>   	 */
>>>>   	bool non_desktop;
>>>> +
>>>> +	/**
>>>> +	 * @adaptive_sync: Adaptive Sync capabilities of the DP/eDP sink
>>>> +	 */
>>>> +	struct drm_adaptive_sync_info adaptive_sync;
>>>>   };
>>>>   
>>>>   int drm_display_info_set_bus_formats(struct drm_display_info *info,
>>>> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
>>>> index f0b03d401c27..b9a230aa3e69 100644
>>>> --- a/include/drm/drm_edid.h
>>>> +++ b/include/drm/drm_edid.h
>>>> @@ -503,4 +503,6 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name,
>>>>   struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
>>>>   					   int hsize, int vsize, int fresh,
>>>>   					   bool rb);
>>>> +void drm_get_adaptive_sync_limits(struct drm_connector *connector,
>>>> +				  const struct edid *edid);

Can drop this one as well.

Regards,
Nicholas Kazlauskas

>>>>   #endif /* __DRM_EDID_H__ */
>>>> -- 
>>>> 2.19.1
>>>
>>> -- 
>>> Ville Syrjälä
>>> Intel
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