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From: Marek Vasut <marex@denx.de>
To: Alistair Francis <alistair23@gmail.com>,
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>,
Sam Ravnborg <sam@ravnborg.org>
Subject: Re: Revert "video: fbdev: mxsfb: Remove driver"
Date: Sun, 15 Aug 2021 14:31:37 +0200 [thread overview]
Message-ID: <d983217b-e117-361c-0306-b131695bb93f@denx.de> (raw)
In-Reply-To: <CAKmqyKMLyx+CvBQbLz-xQvwLS692tx-4xOgU7b-V2J676D29yg@mail.gmail.com>
On 8/15/21 2:16 PM, Alistair Francis wrote:
> Hello,
>
> Commit f225f1393f034 "video: fbdev: mxsfb: Remove driver" removed the
> mxsfb fbdev driver.
>
> I am now working on getting mainline Linux running on the reMarkable 2
> eInk reader [1]. Unfortunately the rM2 doesn't use the standard EPD
> controller on the i.MX SoC, but instead uses the LCD controller.
>
> eInk panels are complex to control and require writing temperature
> dependent waveforms. As these waveforms are proprietary [2] the rM
> team runs closed source software called SWTCON in userspace to control
> the panel [3].
>
> This closed source software expects the fbdev mxsfb driver and it
> doesn't work with the DRM mxsfb driver (at least not that I can get it
> to).
>
> The NXP fork of Linux also re-adds the fbdev driver [4], so they also
> see some uses for it.
>
> I was wondering if the community would be open to re-adding the fbdev
> mxsfb driver to mainline? It could be re-added with a different
> dt-binding so that it is not used by default and only enabled for
> boards when required (like for the rM2).
>
> 1: https://remarkable.com/store/remarkable-2
> 2: https://goodereader.com/blog/e-paper/e-ink-waveforms-are-a-closely-guarded-secret
> 3: https://remarkablewiki.com/tech/rm2_framebuffer
> 4: https://source.codeaurora.org/external/imx/linux-imx/log/drivers/video/fbdev/mxsfb.c?h=lf-5.10.35-2.0.0
+CC Sam.
What sort of special thing does your proprietary userspace do that
cannot be added to the DRM driver or the fbdev emulation (if needed) ?
next prev parent reply other threads:[~2021-08-15 12:31 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 [this message]
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
[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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