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From: Alistair Francis <alistair23@gmail.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Marek Vasut <marex@denx.de>, Fabio Estevam <festevam@gmail.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <kernel@pengutronix.de>,
	dl-linux-imx <linux-imx@nxp.com>,
	b.zolnierkie@samsung.com,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Alistair Francis <alistair@alistair23.me>
Subject: Re: Revert "video: fbdev: mxsfb: Remove driver"
Date: Thu, 19 Aug 2021 19:10:00 +1000	[thread overview]
Message-ID: <CAKmqyKOBYXiWwO4QJBJ9sEO5ay5QyYmO=yzvT31evB7BKeniYw@mail.gmail.com> (raw)
In-Reply-To: <YR1Th65KKRS4D/6+@ravnborg.org>

On Thu, Aug 19, 2021 at 4:38 AM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Alistair,
>
> >
> > These are the EINVAL strace tells me in the not working case:
> >
> > prctl(PR_CAPBSET_READ, 0x30 /* CAP_??? */) = -1 EINVAL (Invalid argument)
> > prctl(PR_CAPBSET_READ, 0x2c /* CAP_??? */) = -1 EINVAL (Invalid argument)
> > prctl(PR_CAPBSET_READ, 0x2a /* CAP_??? */) = -1 EINVAL (Invalid argument)
> > prctl(PR_CAPBSET_READ, 0x29 /* CAP_??? */) = -1 EINVAL (Invalid argument)
> > ioctl(5, FBIOPUT_VSCREENINFO, 0x4ce8e0) = -1 EINVAL (Invalid argument)
> >
> > I'm guessing it's related to FBIOPUT_VSCREENINFO then, is that
> > something that could be added to the DRM emulation?
>
> If it turns out FBIOPUT_VSCREENINFO is the culprint it would also be
> good to know why we see EINVAL.
> One way is to sprinkle a number of printk's in fb_set_var(),
> then you can see how far you get before it fails.

Thanks for the help.

I see this line:

ret = info->fbops->fb_check_var(var, info);

in fb_set_var()

returning early.

Alistair

>
> This could hopefully give a clue why this fails with fbdev emulation.
>
>         Sam

  parent reply	other threads:[~2021-08-19  9:10 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-15 12:16 Revert "video: fbdev: mxsfb: Remove driver" Alistair Francis
2021-08-15 12:31 ` Marek Vasut
2021-08-16  7:34   ` Alistair Francis
2021-08-16  7:55     ` Marek Vasut
2021-08-17  9:08       ` Alistair Francis
2021-08-17 10:03         ` Marek Vasut
2021-08-17 12:16           ` Alistair Francis
     [not found]             ` <YR1R7/nIUIN3LA7t@ravnborg.org>
2021-08-19  8:16               ` Alistair Francis
     [not found]             ` <YR1Th65KKRS4D/6+@ravnborg.org>
2021-08-19  9:10               ` Alistair Francis [this message]
     [not found]                 ` <YR58MvAYYEjBQ7l5@ravnborg.org>
2021-08-19 22:36                   ` Alistair Francis
2021-10-14  9:56                     ` Alistair Francis
2021-10-21 10:42                       ` Alistair Francis

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