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

Sui Jingfeng
2023-05-17T02:04:07Z

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

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.

> 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)
> {