Re: [PATCH 27/33] fbdev: remove FBINFO_MISC_USEREVENT around fb_blank

[Daniel Vetter]

On Mon, May 20, 2019 at 7:20 PM Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
>
> Hi Daniel.
>
> > With the recursion broken in the previous patch we can drop the
> > FBINFO_MISC_USEREVENT flag around calls to fb_blank - recursion
> > prevention was it's only job.
> >
> When grepping for FBINFO_MISC_USEREVENT I get a few hits not addressed
> in the patch below:
>
> drivers/video/fbdev/core/fbcon.c:                       if (!(info->flags & FBINFO_MISC_USEREVENT))
> drivers/video/fbdev/core/fbmem.c:                       if (!ret && (flags & FBINFO_MISC_USEREVENT)) {
> drivers/video/fbdev/core/fbmem.c:                               info->flags &= ~FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbmem.c:               info->flags |= FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbmem.c:               info->flags &= ~FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbmem.c:               info->flags |= FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbmem.c:               info->flags &= ~FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags |= FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags &= ~FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags |= FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags &= ~FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/ps3fb.c:                            info->flags |= FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/ps3fb.c:                            info->flags &= ~FBINFO_MISC_USEREVENT;
> drivers/video/fbdev/sh_mobile_lcdcfb.c:  * FBINFO_MISC_USEREVENT flag is set. Since we do not want to fake a
> include/linux/fb.h:#define FBINFO_MISC_USEREVENT          0x10000 /* event request
>
> The use in ps3fb looks like a candidate for removal and this file is not
> touch in this patch series, so I guess I did not miss it.
>
> As I did not apply the full series maybe some of the other users was
> already taken care of.

It's also used to break recursion around fb_set_par and fb_set_pan.
Untangling that one would be possible, but also requires untangling
some locking, so a lot more work. If you chase all the call paths then
you'll noticed that the users still left have no overlap with the ones
I'm removing here.
-Daniel

>
>
>         Sam
>
> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> > Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> > Cc: Yisheng Xie <ysxie@xxxxxxxxxxx>
> > Cc: "MichaÅ MirosÅaw" <mirq-linux@xxxxxxxxxxxx>
> > Cc: Peter Rosin <peda@xxxxxxxxxx>
> > Cc: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> > Cc: Rob Clark <robdclark@xxxxxxxxx>
> > ---
> >  drivers/video/fbdev/core/fbcon.c   | 5 ++---
> >  drivers/video/fbdev/core/fbmem.c   | 3 ---
> >  drivers/video/fbdev/core/fbsysfs.c | 2 --
> >  3 files changed, 2 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> > index f85d794a3bee..c1a7476e980f 100644
> > --- a/drivers/video/fbdev/core/fbcon.c
> > +++ b/drivers/video/fbdev/core/fbcon.c
> > @@ -2382,9 +2382,8 @@ static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
> >                       fbcon_cursor(vc, blank ? CM_ERASE : CM_DRAW);
> >                       ops->cursor_flash = (!blank);
> >
> > -                     if (!(info->flags & FBINFO_MISC_USEREVENT))
> > -                             if (fb_blank(info, blank))
> > -                                     fbcon_generic_blank(vc, info, blank);
> > +                     if (fb_blank(info, blank))
> > +                             fbcon_generic_blank(vc, info, blank);
> >               }
> >
> >               if (!blank)
> > diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> > index 7f95c7e80155..65a075ccac4a 100644
> > --- a/drivers/video/fbdev/core/fbmem.c
> > +++ b/drivers/video/fbdev/core/fbmem.c
> > @@ -1194,10 +1194,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
> >       case FBIOBLANK:
> >               console_lock();
> >               lock_fb_info(info);
> > -             info->flags |= FBINFO_MISC_USEREVENT;
> >               ret = fb_blank(info, arg);
> > -             info->flags &= ~FBINFO_MISC_USEREVENT;
> > -
> >               /* might again call into fb_blank */
> >               fbcon_fb_blanked(info, arg);
> >               unlock_fb_info(info);
> > diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
> > index 252d4f52d2a5..882b471d619e 100644
> > --- a/drivers/video/fbdev/core/fbsysfs.c
> > +++ b/drivers/video/fbdev/core/fbsysfs.c
> > @@ -310,9 +310,7 @@ static ssize_t store_blank(struct device *device,
> >
> >       arg = simple_strtoul(buf, &last, 0);
> >       console_lock();
> > -     fb_info->flags |= FBINFO_MISC_USEREVENT;
> >       err = fb_blank(fb_info, arg);
> > -     fb_info->flags &= ~FBINFO_MISC_USEREVENT;
> >       /* might again call into fb_blank */
> >       fbcon_fb_blanked(fb_info, arg);
> >       console_unlock();
> > --
> > 2.20.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch