Re: [RFC 10/21] drm/qxl: Remove FB_KMS_HELPER and FB related config options

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Jul 13, 2015 at 12:13:57PM +0530, Archit Taneja wrote:
> Remove FB_* config options since the driver doesn't call any fbdev
> functions directly.
> 
> Remove FB_KMS_HELPER as this would now be selected by the top level
> FBDEV_EMULATION config option. If the fbdev emulation isn't selected,
> the drm_fb_helper functions will be stubbed out.
> 
> The code relying on DEFERRED_IO can't be stubbed out using drm_fb_helper
> functions. This is because the deferred io members in fbdev core structs
> are defined based on whether FB_DEFERRED_IO is defined or not.
> 
> For now, wrap around deferred io code with an #ifdef check for
> CONFIG_DEFERRED_IO. We could consider creating stub fb helper functions
> here, but this would require some changes in the core fbdev structs.

Yeah if more drivers grow a ->dirty callback that does something we'd
probably want to pull all that code out of qxl/udl into core fbdev. i915
now also has a dirty callback, but for fbcon we're going with a slightly
different options: Since all our frontbuffer dirtying are for optional
features we just disable them right now.

Anyway just an idea for future patches when someone works in this area.
For now I think we simply have to select the relevant options if FBDEV
emulation is enabled.
> 
> Cc: David Airlie <airlied@linux.ie>
> Cc: Frediano Ziglio <fziglio@redhat.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
> 
> Signed-off-by: Archit Taneja <architt@codeaurora.org>
> ---
>  drivers/gpu/drm/qxl/Kconfig  | 5 -----
>  drivers/gpu/drm/qxl/qxl_fb.c | 4 ++++
>  2 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/qxl/Kconfig b/drivers/gpu/drm/qxl/Kconfig
> index 38c2bb7..da45b11 100644
> --- a/drivers/gpu/drm/qxl/Kconfig
> +++ b/drivers/gpu/drm/qxl/Kconfig
> @@ -1,12 +1,7 @@
>  config DRM_QXL
>  	tristate "QXL virtual GPU"
>  	depends on DRM && PCI
> -	select FB_SYS_FILLRECT
> -	select FB_SYS_COPYAREA
> -	select FB_SYS_IMAGEBLIT
> -	select FB_DEFERRED_IO

I.e.
	select FB_DEFERRED_IO if DRM_FBDEV_EMULATION

>  	select DRM_KMS_HELPER
> -	select DRM_KMS_FB_HELPER
>  	select DRM_TTM
>  	select CRC32
>  	help
> diff --git a/drivers/gpu/drm/qxl/qxl_fb.c b/drivers/gpu/drm/qxl/qxl_fb.c
> index 41c422f..9391dfe 100644
> --- a/drivers/gpu/drm/qxl/qxl_fb.c
> +++ b/drivers/gpu/drm/qxl/qxl_fb.c
> @@ -163,6 +163,7 @@ static void qxl_dirty_update(struct qxl_fbdev *qfbdev,
>  	schedule_work(&qdev->fb_work);
>  }
>  
> +#ifdef CONFIG_FB_DEFERRED_IO

and using CONFIG_DMR_FBDEV_EMULATION here instead. Same for udl changes.
-Daniel

>  static void qxl_deferred_io(struct fb_info *info,
>  			    struct list_head *pagelist)
>  {
> @@ -191,6 +192,7 @@ static struct fb_deferred_io qxl_defio = {
>  	.delay		= QXL_DIRTY_DELAY,
>  	.deferred_io	= qxl_deferred_io,
>  };
> +#endif
>  
>  static void qxl_fb_fillrect(struct fb_info *info,
>  			    const struct fb_fillrect *rect)
> @@ -420,8 +422,10 @@ static int qxlfb_create(struct qxl_fbdev *qfbdev,
>  		goto out_destroy_fbi;
>  	}
>  
> +#ifdef CONFIG_FB_DEFERRED_IO
>  	info->fbdefio = &qxl_defio;
>  	fb_deferred_io_init(info);
> +#endif
>  
>  	qdev->fbdev_info = info;
>  	qdev->fbdev_qfb = &qfbdev->qfb;
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch