Re: [PATCH 4/9] drm/format-helper: Rework format-helper conversion functions

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 24.10.21 um 13:32 schrieb Noralf Trønnes:
> 
> 
> Den 22.10.2021 15.28, skrev Thomas Zimmermann:
>> Move destination-buffer clipping from all format-helper conversion
>> functions into callers. Support destination-buffer pitch. Only
>> distinguish between system and I/O memory, but use same logic
>> everywhere.
>>
>> Simply harmonize the interface and semantics of the existing code.
>> Not all conversion helpers support all combinations of parameters.
>> We have to add additional features when we need them.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
> 
>>   /**
>>    * drm_fb_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
>>    * @dst: 8-bit grayscale destination buffer
>> + * @dst_pitch: Number of bytes between two consecutive scanlines within dst
>>    * @vaddr: XRGB8888 source buffer
>>    * @fb: DRM framebuffer
>>    * @clip: Clip rectangle area to copy
>> @@ -415,16 +417,21 @@ EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888_dstclip);
>>    *
>>    * ITU BT.601 is used for the RGB -> luma (brightness) conversion.
>>    */
>> -void drm_fb_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
>> -			       struct drm_rect *clip)
>> +void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vaddr,
>> +			      const struct drm_framebuffer *fb, const struct drm_rect *clip)
>>   {
>>   	unsigned int len = (clip->x2 - clip->x1) * sizeof(u32);
>>   	unsigned int x, y;
>>   	void *buf;
>> -	u32 *src;
>> +	u8 *dst8;
>> +	u32 *src32;
>>   
>>   	if (WARN_ON(fb->format->format != DRM_FORMAT_XRGB8888))
>>   		return;
>> +
>> +	if (!dst_pitch)
> 
> len is source length (should really have been named src_len) which
> results in a kernel crash:
> 
>> +		dst_pitch = len;
> 
> This works:
> 
> 		dst_pitch = drm_rect_width(clip);

Fixed in the next revision. Thank you so much!

Best regards
Thomas

> 
> With that fixed:
> 
> Tested-by: Noralf Trønnes <noralf@tronnes.org>
> Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
> 
>> +
>>   	/*
>>   	 * The cma memory is write-combined so reads are uncached.
>>   	 * Speed up by fetching one line at a time.
>> @@ -433,20 +440,22 @@ void drm_fb_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
>>   	if (!buf)
>>   		return;
>>   
>> +	vaddr += clip_offset(clip, fb->pitches[0], sizeof(u32));
>>   	for (y = clip->y1; y < clip->y2; y++) {
>> -		src = vaddr + (y * fb->pitches[0]);
>> -		src += clip->x1;
>> -		memcpy(buf, src, len);
>> -		src = buf;
>> +		dst8 = dst;
>> +		src32 = memcpy(buf, vaddr, len);
>>   		for (x = clip->x1; x < clip->x2; x++) {
>> -			u8 r = (*src & 0x00ff0000) >> 16;
>> -			u8 g = (*src & 0x0000ff00) >> 8;
>> -			u8 b =  *src & 0x000000ff;
>> +			u8 r = (*src32 & 0x00ff0000) >> 16;
>> +			u8 g = (*src32 & 0x0000ff00) >> 8;
>> +			u8 b =  *src32 & 0x000000ff;
>>   
>>   			/* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
>> -			*dst++ = (3 * r + 6 * g + b) / 10;
>> -			src++;
>> +			*dst8++ = (3 * r + 6 * g + b) / 10;
>> +			src32++;
>>   		}
>> +
>> +		vaddr += fb->pitches[0];
>> +		dst += dst_pitch;
>>   	}
>>   
>>   	kfree(buf);

-- 
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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