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Linux kernel for SHIELD
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Tegra 4 support merged in kernel 3.13 #1

Open scaronni opened 10 years ago

scaronni commented 10 years ago

Hello,

support for Tegra 124 devices has been merged in kernel 3.13; any chance to see your work rebased on 3.13? I'm a Fedora packager and would like to try preparing a barebone Fedora system to be used on the Shield (which, by chance, is coming to my mail today!).

Regards, --Simone

Gnurou commented 10 years ago

Hi Simone,

Phoronix got their numbers wrong - Tegra 4 is T114, T124 is actually the next generation of (currently not available) Tegra chips.

T114 support has been around for a while and works pretty well already on the 3.12 kernel on which my branch is based. I will anyway rebase it as -rcs are released so it remains up-to-date. Hopefully in the near future (3.14?) you will just be able to clone Linus' tree and boot on SHIELD.

I'm very excited to hear about your plans to run Fedora on SHIELD. It should not be too hard to do considering I have been able to do it with Arch Linux. Here are a few things that may help you:

You will see that USB host works and that you can plug a USB hub with a keyboard and mouse connected. Simultaneous charging using a special cable is not working yet however, this is one of the next steps on my TODO list.

Please don't hesitate to post again if there is anything on clear. Oh, and of course we want to see the Youtube video of your accomplishments. ;)

scaronni commented 10 years ago

Oh well, as usual Phoronix is really approssimative with the news.

I've booted the kernel with your first initrd that enables a local shell, but nothing else so far as I'm still waiting for my OTG cable to arrive. The idea is to patch the Fedora kernel with the ROTH patches and try to boot an unmodified Fedora userland on it; I'll see how it goes (I'm not a kernel developer). I would like to dedicate a full Micro SD card to the filesystem so the kernel could start directly and read the filesystem on it as a "normal" system.

Is there any information on the wifi chipset and/or touchscreen?

Thanks for all the information.

Gnurou commented 10 years ago

Good start! I would suggest getting a powered OTG cable like the following:

http://www.amazon.co.uk/Micro-Cable-Power-Samsung-I9100/dp/B00B5T42T0

Not only this kind of cable will not drain your SHIELD's battery, but you should also in theory be able to charge it while it is in host mode after a small kernel change. That's useful if you want to use it with Linux and USB devices for more than a few hours.

The set of changes to the kernel are quite minimal, so porting the patches to the Fedora kernel should work provided it's at least 3.11. MicroSD kind of works but is very slow, and sometimes produces read errors. I'd also like to move to root filesystem there, but need to figure out what's wrong first.

Wifi chipset should, on paper, work out of the box. But for some reason it will fail right after the driver loads the firmware. I have been discussing with Broadcom engineers about this, but we could not find a solution yet unfortunately. Maybe I just neglected some detail, in any case it is frustrating as I'm sure we are quite close. By the meantime, USB network adapters are working like a charm.

Touchscreen is another kettle of fish however. It is handled by a closed-source, Android-only user-space driver and I see no hope of Linux support at the moment. Reverse-engineering would also be a huge work. This is somehow ok for SHIELD for which you don't really want to touch the screen anyway, but the same panel is used on TegraNote too and there USB input seems to be the only option. :(