Re: [PATCH 02/30] backlight/gpio_backlight: Compare against struct fb_info.device

Dan Carpenter
2023-06-06T07:49:51Z

On Tue, Jun 06, 2023 at 09:24:48AM +0200, Thomas Zimmermann wrote:
> Hi
>
> Am 05.06.23 um 22:19 schrieb Ruhl, Michael J:
> > > -----Original Message-----
> > > From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of
> > > Thomas Zimmermann
> > > Sent: Monday, June 5, 2023 10:48 AM
> > > To: daniel@ffwll.ch; javierm@redhat.com; sam@ravnborg.org;
> > > deller@gmx.de; geert+renesas@glider.be; lee@kernel.org;
> > > daniel.thompson@linaro.org; jingoohan1@gmail.com
> > > Cc: linux-fbdev@vger.kernel.org; Rich Felker <dalias@libc.org>; linux-
> > > sh@vger.kernel.org; linux-staging@lists.linux.dev; dri-
> > > devel@lists.freedesktop.org; Thomas Zimmermann
> > > <tzimmermann@suse.de>; John Paul Adrian Glaubitz <glaubitz@physik.fu-
> > > berlin.de>; linux-omap@vger.kernel.org
> > > Subject: [PATCH 02/30] backlight/gpio_backlight: Compare against struct
> > > fb_info.device
> > >
> > > Struct gpio_backlight_platform_data refers to a platform device within
> > > the Linux device hierarchy. The test in gpio_backlight_check_fb()
> > > compares it against the fbdev device in struct fb_info.dev, which
> > > is different. Fix the test by comparing to struct fb_info.device.
> > >
> > > Fixes a bug in the backlight driver and prepares fbdev for making
> > > struct fb_info.dev optional.
> >
> > I only see a rename from fbdev to dev...
> >
> > Is there missing code?
>
> As Sam said, the compare operation used the wrong device from fb_info.
>
> I also changed the naming of a few fields in these backlight drivers. I
> could move these renames into a separate patch if that makes things easier
> for reviewers.
>
> >
> > Would a fixes: be useful?
>
> That would be commit 8b770e3c9824 ("backlight: Add GPIO-based backlight
> driver") from 2013. Maybe a bit old already, but I can surely add it.

Don't add the Fixes tag to this one because it doesn't fix anything, it
just renames stuff. The real fix is later? To be honest, it was kind
of difficult to see where the actual fix was.

Fixes tags for old code is fine... I like to know why bugs are
introduced. Was it adding a feature or part of fix for something else
or a cleanup?

regards,
dan carpenter