[PATCH 0/6] drm,fbdev: Use fbdev's I/O helpers

[Thomas Zimmermann]

Am 26.04.23 um 12:33 schrieb Sui Jingfeng:
> Hi,
> 
> 
> The whole patch set is tested with fbdev of IGT, on LoongArch with
> drm/radeon and efifb driver. Test results say SUCCESS.

Thanks a lot.

> 
> 
> On 2023/4/25 22:28, Thomas Zimmermann wrote:
>> Make fbdev's built-in helpers for reading and writing I/O and system
>> memory available to DRM. Replace DRM's internal helpers.
>>
>> The first patch resolves a bug that's been in the fbdev code for
>> more than 15 years. Makes the read/write helpers work successfully
>> with the IGT tests.
>>
>> Patches 2 to 4 streamline fbdev's file-I/O code and remove a few
>> duplicate checks.
>>
>> Patch 5 moves the default-I/O code into the new helpers fb_cfb_read()
>> and fb_cfb_write(); patch 6 uses them in DRM. This allows us to remove
>> quite a bit of code from DRM's internal fbdev helpers.
>>
>> Tested with i915 and simpledrm.
>>
>> The next step here is to remove the drm_fb_helper_{cfb,sys}_*()
>> entirely. They where mostly introduced because fbdev doesn't protect
>> it's public interfaces with an CONFIG_FB preprocessor guards. But all
>> of DRM driver's fbdev emulation won't be build without CONFIG_FB, so
>> this is not an issue in practice. Removing the DRM wrappers will
>> further simplify the DRM code.
>>
>> Thomas Zimmermann (6):
>>    fbdev: Return number of bytes read or written
>>    fbdev: Use screen_buffer in fb_sys_{read,write}()
>>    fbdev: Don't re-validate info->state in fb_ops implementations
>>    fbdev: Validate info->screen_{base,buffer} in fb_ops implementations
>>    fbdev: Move CFB read and write code into helper functions
>>    drm/fb-helper: Use fb_{cfb,sys}_{read, write}()
>>
>>   drivers/gpu/drm/drm_fb_helper.c        | 174 +------------------------
>>   drivers/video/fbdev/cobalt_lcdfb.c     |   6 +
>>   drivers/video/fbdev/core/Makefile      |   2 +-
>>   drivers/video/fbdev/core/fb_cfb_fops.c | 126 ++++++++++++++++++
>>   drivers/video/fbdev/core/fb_sys_fops.c |  36 ++---
>>   drivers/video/fbdev/core/fbmem.c       | 111 +---------------
>>   drivers/video/fbdev/sm712fb.c          |  10 +-
>>   include/linux/fb.h                     |  10 ++
>>   8 files changed, 173 insertions(+), 302 deletions(-)
>>   create mode 100644 drivers/video/fbdev/core/fb_cfb_fops.c
>>

-- 
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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