Re: [Intel-gfx] [v2, 11/12] drm/fbdev-generic: Implement dedicated fbdev I/O helpers

Thomas Zimmermann
2023-05-18T13:30:35Z

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Hi

Am 18.05.23 um 14:46 schrieb Sui Jingfeng:
> Hi,
>
> On 2023/5/17 15:07, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 17.05.23 um 03:58 schrieb Sui Jingfeng:
>>> Hi, Thomas
>>>
>>>
>>> After apply your patch set, the kernel with
>>> arch/loongarch/configs/loongson3_defconfig
>>>
>>> can not finish compile anymore.  gcc complains:
>>>
>>>
>>>    AR      drivers/gpu/built-in.a
>>>    AR      drivers/built-in.a
>>>    AR      built-in.a
>>>    AR      vmlinux.a
>>>    LD      vmlinux.o
>>>    OBJCOPY modules.builtin.modinfo
>>>    GEN     modules.builtin
>>>    GEN     .vmlinux.objs
>>>    MODPOST Module.symvers
>>> ERROR: modpost: "fb_sys_write" [drivers/gpu/drm/drm_kms_helper.ko]
>>> undefined!
>>> ERROR: modpost: "sys_imageblit" [drivers/gpu/drm/drm_kms_helper.ko]
>>> undefined!
>>> ERROR: modpost: "sys_fillrect" [drivers/gpu/drm/drm_kms_helper.ko]
>>> undefined!
>>> ERROR: modpost: "sys_copyarea" [drivers/gpu/drm/drm_kms_helper.ko]
>>> undefined!
>>> ERROR: modpost: "fb_sys_read" [drivers/gpu/drm/drm_kms_helper.ko]
>>> undefined!
>>> make[1]: *** [scripts/Makefile.modpost:136: Module.symvers] Error 1
>>> make: *** [Makefile:1978: modpost] Error 2
>>
>> Thanks for reporting this problem. I found that it's caused by a typo
>> in the very first patch 1/7, where these helpers are not selected
>> correctly. Will be fixed in the next round.
>>
> Yeah, this is just a typo.
>
> Should replace 'FB_SYS_HELPER' with 'FB_SYS_HELPERS' on the first patch
> of this series.
>
>
>> Best regards
>> Thomas
>>
>>>
>>>
>>> On 2023/5/15 17:40, Thomas Zimmermann wrote:
>>>> Implement dedicated fbdev helpers for framebuffer I/O instead
>>>> of using DRM's helpers. Fbdev-generic was the only caller of the
>>>> DRM helpers, so remove them from the helper module.
>>>>
>>>> v2:
>>>>     * use FB_SYS_HELPERS_DEFERRED option
>>>>
>>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>>> ---
>>>>   drivers/gpu/drm/Kconfig             |   6 +-
>>>>   drivers/gpu/drm/drm_fb_helper.c     | 107
>>>> ----------------------------
>>>>   drivers/gpu/drm/drm_fbdev_generic.c |  47 ++++++++++--
>>>>   include/drm/drm_fb_helper.h         |  41 -----------
>>>>   4 files changed, 43 insertions(+), 158 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>>>> index 77fb10ddd8a2..92a782827b7b 100644
>>>> --- a/drivers/gpu/drm/Kconfig
>>>> +++ b/drivers/gpu/drm/Kconfig
>>>> @@ -95,6 +95,7 @@ config DRM_KUNIT_TEST
>>>>   config DRM_KMS_HELPER
>>>>       tristate
>>>>       depends on DRM
>>>> +    select FB_SYS_HELPERS_DEFERRED if DRM_FBDEV_EMULATION
>>>
>>> Here, select FB_SYS_HELPERS helps resolve the above issue mentioned.
>>>
> But select FB_SYS_HELPERS here is more better, I think.  Because it show
> the nature that
>
> DRM_KMS_HELPER is depend on FB_SYS_HELPERS, I think you may want isolate
>
> those dependency with DRM_FBDEV_EMULATION guard.
>
> at least, you should guarantee that drm itself could built and run
> standalone.

Indeed, it would be better to select this from DRM_FBDEV_EMULATION.
Thanks for the remark. I'll update this in the next version.

Best regards
Thomas

>
> Fbdev emulation is a client of drm, not reverse.
>
>
> By the way, does Denial happy about this,
>
> maybe, he want the fbdev emulation 100% made in drm?
>
>>>>       help
>>>>         CRTC helpers for KMS drivers.
>>>> @@ -135,11 +136,6 @@ config DRM_FBDEV_EMULATION
>>>>       select FB_CFB_FILLRECT
>>>>       select FB_CFB_COPYAREA
>>>>       select FB_CFB_IMAGEBLIT
>>>> -    select FB_DEFERRED_IO
>>>> -    select FB_SYS_FOPS
>>>> -    select FB_SYS_FILLRECT
>>>> -    select FB_SYS_COPYAREA
>>>> -    select FB_SYS_IMAGEBLIT
>>>>       select FRAMEBUFFER_CONSOLE if !EXPERT
>>>>       select FRAMEBUFFER_CONSOLE_DETECT_PRIMARY if FRAMEBUFFER_CONSOLE
>>>>       default y
>>>> diff --git a/drivers/gpu/drm/drm_fb_helper.c
>>>> b/drivers/gpu/drm/drm_fb_helper.c
>>>> index 8724e08c518b..ba0a808f14ee 100644
>>>> --- a/drivers/gpu/drm/drm_fb_helper.c
>>>> +++ b/drivers/gpu/drm/drm_fb_helper.c
>>>> @@ -729,113 +729,6 @@ void drm_fb_helper_deferred_io(struct fb_info
>>>> *info, struct list_head *pagerefli
>>>>   }
>>>>   EXPORT_SYMBOL(drm_fb_helper_deferred_io);
>>>> -/**
>>>> - * drm_fb_helper_sys_read - Implements struct &fb_ops.fb_read for
>>>> system memory
>>>> - * @info: fb_info struct pointer
>>>> - * @buf: userspace buffer to read from framebuffer memory
>>>> - * @count: number of bytes to read from framebuffer memory
>>>> - * @ppos: read offset within framebuffer memory
>>>> - *
>>>> - * Returns:
>>>> - * The number of bytes read on success, or an error code otherwise.
>>>> - */
>>>> -ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
>>>> -                   size_t count, loff_t *ppos)
>>>> -{
>>>> -    return fb_sys_read(info, buf, count, ppos);
>>>> -}
>>>> -EXPORT_SYMBOL(drm_fb_helper_sys_read);
>>>> -
>>>> -/**
>>>> - * drm_fb_helper_sys_write - Implements struct &fb_ops.fb_write for
>>>> system memory
>>>> - * @info: fb_info struct pointer
>>>> - * @buf: userspace buffer to write to framebuffer memory
>>>> - * @count: number of bytes to write to framebuffer memory
>>>> - * @ppos: write offset within framebuffer memory
>>>> - *
>>>> - * Returns:
>>>> - * The number of bytes written on success, or an error code otherwise.
>>>> - */
>>>> -ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char
>>>> __user *buf,
>>>> -                size_t count, loff_t *ppos)
>>>> -{
>>>> -    struct drm_fb_helper *helper = info->par;
>>>> -    loff_t pos = *ppos;
>>>> -    ssize_t ret;
>>>> -    struct drm_rect damage_area;
>>>> -
>>>> -    ret = fb_sys_write(info, buf, count, ppos);
>>>> -    if (ret <= 0)
>>>> -        return ret;
>>>> -
>>>> -    if (helper->funcs->fb_dirty) {
>>>> -        drm_fb_helper_memory_range_to_clip(info, pos, ret,
>>>> &damage_area);
>>>> -        drm_fb_helper_damage(helper, damage_area.x1, damage_area.y1,
>>>> -                     drm_rect_width(&damage_area),
>>>> -                     drm_rect_height(&damage_area));
>>>> -    }
>>>> -
>>>> -    return ret;
>>>> -}
>>>> -EXPORT_SYMBOL(drm_fb_helper_sys_write);
>>>> -
>>>> -/**
>>>> - * drm_fb_helper_sys_fillrect - wrapper around sys_fillrect
>>>> - * @info: fbdev registered by the helper
>>>> - * @rect: info about rectangle to fill
>>>> - *
>>>> - * A wrapper around sys_fillrect implemented by fbdev core
>>>> - */
>>>> -void drm_fb_helper_sys_fillrect(struct fb_info *info,
>>>> -                const struct fb_fillrect *rect)
>>>> -{
>>>> -    struct drm_fb_helper *helper = info->par;
>>>> -
>>>> -    sys_fillrect(info, rect);
>>>> -
>>>> -    if (helper->funcs->fb_dirty)
>>>> -        drm_fb_helper_damage(helper, rect->dx, rect->dy,
>>>> rect->width, rect->height);
>>>> -}
>>>> -EXPORT_SYMBOL(drm_fb_helper_sys_fillrect);
>>>> -
>>>> -/**
>>>> - * drm_fb_helper_sys_copyarea - wrapper around sys_copyarea
>>>> - * @info: fbdev registered by the helper
>>>> - * @area: info about area to copy
>>>> - *
>>>> - * A wrapper around sys_copyarea implemented by fbdev core
>>>> - */
>>>> -void drm_fb_helper_sys_copyarea(struct fb_info *info,
>>>> -                const struct fb_copyarea *area)
>>>> -{
>>>> -    struct drm_fb_helper *helper = info->par;
>>>> -
>>>> -    sys_copyarea(info, area);
>>>> -
>>>> -    if (helper->funcs->fb_dirty)
>>>> -        drm_fb_helper_damage(helper, area->dx, area->dy,
>>>> area->width, area->height);
>>>> -}
>>>> -EXPORT_SYMBOL(drm_fb_helper_sys_copyarea);
>>>> -
>>>> -/**
>>>> - * drm_fb_helper_sys_imageblit - wrapper around sys_imageblit
>>>> - * @info: fbdev registered by the helper
>>>> - * @image: info about image to blit
>>>> - *
>>>> - * A wrapper around sys_imageblit implemented by fbdev core
>>>> - */
>>>> -void drm_fb_helper_sys_imageblit(struct fb_info *info,
>>>> -                 const struct fb_image *image)
>>>> -{
>>>> -    struct drm_fb_helper *helper = info->par;
>>>> -
>>>> -    sys_imageblit(info, image);
>>>> -
>>>> -    if (helper->funcs->fb_dirty)
>>>> -        drm_fb_helper_damage(helper, image->dx, image->dy,
>>>> image->width, image->height);
>>>> -}
>>>> -EXPORT_SYMBOL(drm_fb_helper_sys_imageblit);
>>>> -
>>>>   /**
>>>>    * drm_fb_helper_cfb_read - Implements struct &fb_ops.fb_read for
>>>> I/O memory
>>>>    * @info: fb_info struct pointer
>>>> diff --git a/drivers/gpu/drm/drm_fbdev_generic.c
>>>> b/drivers/gpu/drm/drm_fbdev_generic.c
>>>> index 8e5148bf40bb..f53fc49e34a4 100644
>>>> --- a/drivers/gpu/drm/drm_fbdev_generic.c
>>>> +++ b/drivers/gpu/drm/drm_fbdev_generic.c
>>>> @@ -34,6 +34,43 @@ static int drm_fbdev_generic_fb_release(struct
>>>> fb_info *info, int user)
>>>>       return 0;
>>>>   }
>>>> +static ssize_t drm_fbdev_generic_fb_write(struct fb_info *info,
>>>> const char __user *buf,
>>>> +                      size_t count, loff_t *ppos)
>>>> +{
>>>> +    struct drm_fb_helper *helper = info->par;
>>>> +    loff_t pos = *ppos;
>>>> +    ssize_t ret;
>>>> +
>>>> +    ret = fb_sys_write(info, buf, count, ppos);
>>>> +    if (ret > 0)
>>>> +        drm_fb_helper_damage_range(helper, pos, ret);
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static void drm_fbdev_generic_fb_fillrect(struct fb_info *info,
>>>> const struct fb_fillrect *rect)
>>>> +{
>>>> +    struct drm_fb_helper *helper = info->par;
>>>> +
>>>> +    sys_fillrect(info, rect);
>>>> +    drm_fb_helper_damage(helper, rect->dx, rect->dy, rect->width,
>>>> rect->height);
>>>> +}
>>>> +
>>>> +static void drm_fbdev_generic_fb_copyarea(struct fb_info *info,
>>>> const struct fb_copyarea *area)
>>>> +{
>>>> +    struct drm_fb_helper *helper = info->par;
>>>> +
>>>> +    sys_copyarea(info, area);
>>>> +    drm_fb_helper_damage(helper, area->dx, area->dy, area->width,
>>>> area->height);
>>>> +}
>>>> +
>>>> +static void drm_fbdev_generic_fb_imageblit(struct fb_info *info,
>>>> const struct fb_image *image)
>>>> +{
>>>> +    struct drm_fb_helper *helper = info->par;
>>>> +
>>>> +    sys_imageblit(info, image);
>>>> +    drm_fb_helper_damage(helper, image->dx, image->dy,
>>>> image->width, image->height);
>>>> +}
>>>> +
>>>>   static void drm_fbdev_generic_fb_destroy(struct fb_info *info)
>>>>   {
>>>>       struct drm_fb_helper *fb_helper = info->par;
>>>> @@ -56,12 +93,12 @@ static const struct fb_ops
>>>> drm_fbdev_generic_fb_ops = {
>>>>       .owner        = THIS_MODULE,
>>>>       .fb_open    = drm_fbdev_generic_fb_open,
>>>>       .fb_release    = drm_fbdev_generic_fb_release,
>>>> -    .fb_read    = drm_fb_helper_sys_read,
>>>> -    .fb_write    = drm_fb_helper_sys_write,
>>>> +    .fb_read    = fb_sys_read,
>>>> +    .fb_write    = drm_fbdev_generic_fb_write,
>>>>       DRM_FB_HELPER_DEFAULT_OPS,
>>>> -    .fb_fillrect    = drm_fb_helper_sys_fillrect,
>>>> -    .fb_copyarea    = drm_fb_helper_sys_copyarea,
>>>> -    .fb_imageblit    = drm_fb_helper_sys_imageblit,
>>>> +    .fb_fillrect    = drm_fbdev_generic_fb_fillrect,
>>>> +    .fb_copyarea    = drm_fbdev_generic_fb_copyarea,
>>>> +    .fb_imageblit    = drm_fbdev_generic_fb_imageblit,
>>>>       .fb_mmap    = fb_deferred_io_mmap,
>>>>       .fb_destroy    = drm_fbdev_generic_fb_destroy,
>>>>   };
>>>> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
>>>> index 80c402f4e379..e3240d749a43 100644
>>>> --- a/include/drm/drm_fb_helper.h
>>>> +++ b/include/drm/drm_fb_helper.h
>>>> @@ -259,18 +259,6 @@ void drm_fb_helper_damage_range(struct
>>>> drm_fb_helper *helper, off_t off, size_t
>>>>   void drm_fb_helper_deferred_io(struct fb_info *info, struct
>>>> list_head *pagereflist);
>>>> -ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
>>>> -                   size_t count, loff_t *ppos);
>>>> -ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char
>>>> __user *buf,
>>>> -                size_t count, loff_t *ppos);
>>>> -
>>>> -void drm_fb_helper_sys_fillrect(struct fb_info *info,
>>>> -                const struct fb_fillrect *rect);
>>>> -void drm_fb_helper_sys_copyarea(struct fb_info *info,
>>>> -                const struct fb_copyarea *area);
>>>> -void drm_fb_helper_sys_imageblit(struct fb_info *info,
>>>> -                 const struct fb_image *image);
>>>> -
>>>>   ssize_t drm_fb_helper_cfb_read(struct fb_info *info, char __user
>>>> *buf,
>>>>                      size_t count, loff_t *ppos);
>>>>   ssize_t drm_fb_helper_cfb_write(struct fb_info *info, const char
>>>> __user *buf,
>>>> @@ -398,35 +386,6 @@ static inline int
>>>> drm_fb_helper_defio_init(struct drm_fb_helper *fb_helper)
>>>>       return -ENODEV;
>>>>   }
>>>> -static inline ssize_t drm_fb_helper_sys_read(struct fb_info *info,
>>>> -                         char __user *buf, size_t count,
>>>> -                         loff_t *ppos)
>>>> -{
>>>> -    return -ENODEV;
>>>> -}
>>>> -
>>>> -static inline ssize_t drm_fb_helper_sys_write(struct fb_info *info,
>>>> -                          const char __user *buf,
>>>> -                          size_t count, loff_t *ppos)
>>>> -{
>>>> -    return -ENODEV;
>>>> -}
>>>> -
>>>> -static inline void drm_fb_helper_sys_fillrect(struct fb_info *info,
>>>> -                          const struct fb_fillrect *rect)
>>>> -{
>>>> -}
>>>> -
>>>> -static inline void drm_fb_helper_sys_copyarea(struct fb_info *info,
>>>> -                          const struct fb_copyarea *area)
>>>> -{
>>>> -}
>>>> -
>>>> -static inline void drm_fb_helper_sys_imageblit(struct fb_info *info,
>>>> -                           const struct fb_image *image)
>>>> -{
>>>> -}
>>>> -
>>>>   static inline ssize_t drm_fb_helper_cfb_read(struct fb_info *info,
>>>> char __user *buf,
>>>>                            size_t count, loff_t *ppos)
>>>>   {
>>

--
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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