Re: [PATCH v2 10/10] drm/ofdrm: Support color management

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 26.07.22 um 15:49 schrieb Javier Martinez Canillas:
> On 7/20/22 16:27, Thomas Zimmermann wrote:
>> Support the CRTC's color-management property and implement each model's
>> palette support.
>>
>> The OF hardware has different methods of setting the palette. The
>> respective code has been taken from fbdev's offb and refactored into
>> per-model device functions. The device functions integrate this
>> functionality into the overall modesetting.
>>
>> As palette handling is a CRTC property that depends on the primary
>> plane's color format, the plane's atomic_check helper now updates the
>> format field in ofdrm's custom CRTC state. The CRTC's atomic_flush
>> helper updates the palette for the format as needed.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
> 
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> 
> [...]
> 
>> +static void __iomem *ofdrm_mach64_cmap_ioremap(struct ofdrm_device *odev,
>> +					       struct device_node *of_node,
>> +					       u64 fb_base)
>> +{
>> +	struct drm_device *dev = &odev->dev;
>> +	u64 address;
>> +	void __iomem *cmap_base;
>> +
>> +	address = fb_base & 0xff000000ul;
>> +	address += 0x7ff000;
>> +
> 
> It would be good to know where these addresses are coming from. Maybe some
> constant macros or a comment ? Same for the other places where addresses
> and offsets are used.

I have no idea where these values come from. I took them from offb. And 
I suspect that some of these CMAP helpers could be further merged if 
only it was clear where the numbers come from.  But as i don't have the 
equipment for testing, I took most of this literally as-is from offb.

> 
> [...]
> 
>>   static struct ofdrm_crtc_state *to_ofdrm_crtc_state(struct drm_crtc_state *base)
>> @@ -376,10 +735,12 @@ static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>>   						   struct drm_atomic_state *new_state)
>>   {
>>   	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
>> +	struct drm_framebuffer *new_fb = new_plane_state->fb;
>>   	struct drm_crtc_state *new_crtc_state;
>> +	struct ofdrm_crtc_state *new_ofdrm_crtc_state;
>>   	int ret;
>>   
>> -	if (!new_plane_state->fb)
>> +	if (!new_fb)
>>   		return 0;
>>   
>>   	new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
>> @@ -391,6 +752,14 @@ static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>>   	if (ret)
>>   		return ret;
>>   
>> +	if (!new_plane_state->visible)
>> +		return 0;
>> +
>> +	new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
>> +
>> +	new_ofdrm_crtc_state = to_ofdrm_crtc_state(new_crtc_state);
>> +	new_ofdrm_crtc_state->format = new_fb->format;
>> +
> 
> Ah, I understand now why you didn't factor out the .atomic_check callbacks
> for the two drivers in a fwfb helper. Maybe you can also add a comment to
> mention that this updates the format so the CRTC palette can be applied in
> the .atomic_flush callback ?

Yeah, this code is one reason for not sharing atomic_check in fwfb.  The 
other reason is that the fwfb code is only a wrapper around the atomic 
helpers with little extra value.  I did have such fwfb helpers a some 
point, but removed them.

Best regards
Thomas

> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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