Re: [PATCH v2 01/47] media/vivid: Use fbdev I/O helpers

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 01.08.23 um 13:22 schrieb Hans Verkuil:
> On 01/08/2023 12:13, Thomas Zimmermann wrote:
>> Set struct fb_ops and with FB_DEFAULT_IO_OPS, fbdev's initializer
>> for I/O memory. Sets the callbacks to the cfb_ and fb_io_ functions.
>> Select the correct modules with Kconfig's FB_IO_HELPERS token.
>>
>> The macro and token set the currently selected values, so there is
>> no functional change.
>>
>> v2:
>> 	* updated to use _IOMEM_ tokens
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
>> Acked-by: Helge Deller <deller@gmx.de>
>> Cc: Hans Verkuil <hverkuil@xs4all.nl>
>> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
>> ---
>>   drivers/media/test-drivers/vivid/Kconfig     | 4 +---
>>   drivers/media/test-drivers/vivid/vivid-osd.c | 4 +---
>>   2 files changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/media/test-drivers/vivid/Kconfig b/drivers/media/test-drivers/vivid/Kconfig
>> index 318799d317ba..5b08a5ad291e 100644
>> --- a/drivers/media/test-drivers/vivid/Kconfig
>> +++ b/drivers/media/test-drivers/vivid/Kconfig
>> @@ -3,11 +3,9 @@ config VIDEO_VIVID
>>   	tristate "Virtual Video Test Driver"
>>   	depends on VIDEO_DEV && !SPARC32 && !SPARC64 && FB
>>   	depends on HAS_DMA
>> +	select FB_IOMEM_HELPERS
>>   	select FONT_SUPPORT
>>   	select FONT_8x16
>> -	select FB_CFB_FILLRECT
>> -	select FB_CFB_COPYAREA
>> -	select FB_CFB_IMAGEBLIT
>>   	select VIDEOBUF2_VMALLOC
>>   	select VIDEOBUF2_DMA_CONTIG
>>   	select VIDEO_V4L2_TPG
>> diff --git a/drivers/media/test-drivers/vivid/vivid-osd.c b/drivers/media/test-drivers/vivid/vivid-osd.c
>> index 051f1805a16d..5c931b94a7b5 100644
>> --- a/drivers/media/test-drivers/vivid/vivid-osd.c
>> +++ b/drivers/media/test-drivers/vivid/vivid-osd.c
>> @@ -246,12 +246,10 @@ static int vivid_fb_blank(int blank_mode, struct fb_info *info)
>>   
>>   static const struct fb_ops vivid_fb_ops = {
>>   	.owner = THIS_MODULE,
>> +	FB_DEFAULT_IOMEM_OPS,
> 
> This macro also sets fb_read and fb_write ops here, in addition to the
> cfb_* ops, based on this patch:
> 
> https://lore.kernel.org/all/20230729193157.15446-2-tzimmermann@suse.de/#Z2e.:20230729193157.15446-2-tzimmermann::40suse.de:1include:linux:fb.h
> 
> But those two ops were never set in this driver before.
> 
> It's been ages since I last worked with this, so I can't tell whether that's
> good or bad, all I know is that it makes what appears to be a functional change.
> 
> Can you explain a bit more? Am I missing something?

That change is intentional and welcome. If no fb_read/fb_write pointers 
are given fbdev uses them as their default. See

 
https://elixir.bootlin.com/linux/v6.5-rc1/source/drivers/video/fbdev/core/fbmem.c#L773

and below. Once all drivers set these pointers explicitly, we can drop 
the default and make the helpers optional and modular. For the drivers 
in this patchset there's no functional change.

Best regards
Thomas

> 
> Regards,
> 
> 	Hans
> 
>>   	.fb_check_var   = vivid_fb_check_var,
>>   	.fb_set_par     = vivid_fb_set_par,
>>   	.fb_setcolreg   = vivid_fb_setcolreg,
>> -	.fb_fillrect    = cfb_fillrect,
>> -	.fb_copyarea    = cfb_copyarea,
>> -	.fb_imageblit   = cfb_imageblit,
>>   	.fb_cursor      = NULL,
>>   	.fb_ioctl       = vivid_fb_ioctl,
>>   	.fb_pan_display = vivid_fb_pan_display,
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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