linux-kernel - Re: [PATCH 27/33] fbdev: remove FBINFO_MISC_USEREVENT around fb

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Message-ID: <20190520175303.GA31421@ravnborg.org>
Date:   Mon, 20 May 2019 19:53:03 +0200
From:   Sam Ravnborg <sam@...nborg.org>
To:     Daniel Vetter <daniel.vetter@...ll.ch>
Cc:     DRI Development <dri-devel@...ts.freedesktop.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Yisheng Xie <ysxie@...mail.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mikulas Patocka <mpatocka@...hat.com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Peter Rosin <peda@...ntia.se>
Subject: Re: [PATCH 27/33] fbdev: remove FBINFO_MISC_USEREVENT around fb_blank

Hi Daniel.

On Mon, May 20, 2019 at 07:29:52PM +0200, Daniel Vetter wrote:
> On Mon, May 20, 2019 at 7:20 PM Sam Ravnborg <sam@...nborg.org> 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.
Now you spell it out it is obvious. I guess I never read more than fb_
and missed that we are dealing with different calls.
Thanks for the quick feedback, and sorry for the noise.

	Sam