Linux on an E-Ink Tablet

Linux on an E-Ink Tablet

[Alistair Francis]

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Hey,

I have been working on updating the Linux kernel of the reMarkable 2, which is an E-Ink tablet using the i.MX7D.

It ships with an outdated version of https://github.com/Freescale/linux-fslc/tree/4.14-1.0.x-imx with around 300 patches on top, the source is here: https://github.com/reMarkable/linux/tree/zero-sugar.

I have ported those 300 patches on top of https://github.com/Freescale/linux-fslc/tree/5.4-2.2.x-imx and have it mostly working. I'm just struggling with the brcmfmac WiFi.

I'm now starting to look at what next though.

I don't see a 5.10*-imx branch, just a 5.10.x+fslc. Does anyone know if there is a plan for a 5.10*-imx branch?

Also the E-Ink display is driven by the video/fbdev/mxsfb.c  driver, which has been removed in mainline ( https://github.com/torvalds/linux/commit/f225f1393f034e17281274180626086276da766c ), I was wondering if anyone knows how to swap drivers without changing the user space software (which is closed source).

I'm also working on trying to upstream some of the work. It seems like there is a lot in the *-imx branches that isn't upstream. Is that something that is still going on?

Alistair

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Re: [meta-freescale] Linux on an E-Ink Tablet

[Otavio Salvador]

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Hello Alistair,

Em sex., 5 de fev. de 2021 às 02:21, Alistair Francis <alistair23@gmail.com>
escreveu:

> I have been working on updating the Linux kernel of the reMarkable 2,
> which is an E-Ink tablet using the i.MX7D.
>
> It ships with an outdated version of
> https://github.com/Freescale/linux-fslc/tree/4.14-1.0.x-imx with around
> 300 patches on top, the source is here:
> https://github.com/reMarkable/linux/tree/zero-sugar.
>
> I have ported those 300 patches on top of
> https://github.com/Freescale/linux-fslc/tree/5.4-2.2.x-imx and have it
> mostly working. I'm just struggling with the brcmfmac WiFi.
>
> I'm now starting to look at what next though.
>
> I don't see a 5.10*-imx branch, just a 5.10.x+fslc. Does anyone know if
> there is a plan for a 5.10*-imx branch?
>

It will be created when NXP does a GA release on top of this. The -imx
branch is based on their fork and on top of it we do the needed fixes and
merge stable updates as well.

Also the E-Ink display is driven by the video/fbdev/mxsfb.c  driver, which
> has been removed in mainline (
> https://github.com/torvalds/linux/commit/f225f1393f034e17281274180626086276da766c),
> I was wondering if anyone knows how to swap drivers without changing the
> user space software (which is closed source).
>
> I'm also working on trying to upstream some of the work. It seems like
> there is a lot in the *-imx branches that isn't upstream. Is that something
> that is still going on?
>

All things which are clean could be sent upstream. It'd be of great help as
it'd reduce the maintenance work.

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9 9981-7854          Mobile: +1 (347) 903-9750

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Re: [meta-freescale] Linux on an E-Ink Tablet

[Alistair Francis]

On Fri, Feb 5, 2021 at 4:49 AM Otavio Salvador
<otavio.salvador@ossystems.com.br> wrote:
>
> Hello Alistair,
>
> Em sex., 5 de fev. de 2021 às 02:21, Alistair Francis <alistair23@gmail.com> escreveu:
>>
>> I have been working on updating the Linux kernel of the reMarkable 2, which is an E-Ink tablet using the i.MX7D.
>>
>> It ships with an outdated version of https://github.com/Freescale/linux-fslc/tree/4.14-1.0.x-imx with around 300 patches on top, the source is here: https://github.com/reMarkable/linux/tree/zero-sugar.
>>
>> I have ported those 300 patches on top of  https://github.com/Freescale/linux-fslc/tree/5.4-2.2.x-imx and have it mostly working. I'm just struggling with the brcmfmac WiFi.
>>
>> I'm now starting to look at what next though.
>>
>> I don't see a 5.10*-imx branch, just a 5.10.x+fslc. Does anyone know if there is a plan for a 5.10*-imx branch?
>
>
> It will be created when NXP does a GA release on top of this. The -imx branch is based on their fork and on top of it we do the needed fixes and merge stable updates as well.

Ah ok. So the *-fslc branch is the community branch and the *-imx
branch is the NXP branch merged with the community branch?

>
>> Also the E-Ink display is driven by the video/fbdev/mxsfb.c  driver, which has been removed in mainline (https://github.com/torvalds/linux/commit/f225f1393f034e17281274180626086276da766c), I was wondering if anyone knows how to swap drivers without changing the user space software (which is closed source).
>>
>> I'm also working on trying to upstream some of the work. It seems like there is a lot in the *-imx branches that isn't upstream. Is that something that is still going on?
>
>
> All things which are clean could be sent upstream. It'd be of great help as it'd reduce the maintenance work.

Ah, I think I misspoke. I'm trying to upstream the rM2 specific
changes, but it depends on changes from the *-imx branch. I was
wondering if the *-imx branch will be fully upstreamed. It sounds like
that is up to NXP though.

Alistair

>
> --
> Otavio Salvador                             O.S. Systems
> http://www.ossystems.com.br        http://code.ossystems.com.br
> Mobile: +55 (53) 9 9981-7854          Mobile: +1 (347) 903-9750

Re: [meta-freescale] Linux on an E-Ink Tablet

[Otavio Salvador]

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Em sex., 5 de fev. de 2021 às 21:20, Alistair Francis <alistair23@gmail.com>
escreveu:

> On Fri, Feb 5, 2021 at 4:49 AM Otavio Salvador
> <otavio.salvador@ossystems.com.br> wrote:
> > It will be created when NXP does a GA release on top of this. The -imx
> branch is based on their fork and on top of it we do the needed fixes and
> merge stable updates as well.
>
> Ah ok. So the *-fslc branch is the community branch and the *-imx
> branch is the NXP branch merged with the community branch?
>

Yes, you got it right.

> All things which are clean could be sent upstream. It'd be of great help
> as it'd reduce the maintenance work.
>
> Ah, I think I misspoke. I'm trying to upstream the rM2 specific
> changes, but it depends on changes from the *-imx branch. I was
> wondering if the *-imx branch will be fully upstreamed. It sounds like
> that is up to NXP though.
>

Sure but in the process, we often find things that are easy to upstream and
help to reduce the delta.

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9 9981-7854          Mobile: +1 (347) 903-9750

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Re: [meta-freescale] Linux on an E-Ink Tablet

[Alistair Francis]

On Fri, Feb 5, 2021 at 4:28 PM Otavio Salvador
<otavio.salvador@ossystems.com.br> wrote:
>
>
>
> Em sex., 5 de fev. de 2021 às 21:20, Alistair Francis <alistair23@gmail.com> escreveu:
>>
>> On Fri, Feb 5, 2021 at 4:49 AM Otavio Salvador
>> <otavio.salvador@ossystems.com.br> wrote:
>> > It will be created when NXP does a GA release on top of this. The -imx branch is based on their fork and on top of it we do the needed fixes and merge stable updates as well.
>>
>> Ah ok. So the *-fslc branch is the community branch and the *-imx
>> branch is the NXP branch merged with the community branch?
>
>
> Yes, you got it right.

Ok, now I understand. I also realised that the *-fslc has a small
delta with mainline which is great to see!

The 5.4*-imx is not as good in that regard :(

>
>> > All things which are clean could be sent upstream. It'd be of great help as it'd reduce the maintenance work.
>>
>> Ah, I think I misspoke. I'm trying to upstream the rM2 specific
>> changes, but it depends on changes from the *-imx branch. I was
>> wondering if the *-imx branch will be fully upstreamed. It sounds like
>> that is up to NXP though.
>
>
> Sure but in the process, we often find things that are easy to upstream and help to reduce the delta.

Makes sense. Hopefully the next 5.10*-imx release has a smaller diff
from mainline then and I can go from there, upstreaming the parts I'm
interested in.

Alistair

>
> --
> Otavio Salvador                             O.S. Systems
> http://www.ossystems.com.br        http://code.ossystems.com.br
> Mobile: +55 (53) 9 9981-7854          Mobile: +1 (347) 903-9750