Add postmarketOS implemention in Wiki

[ZenithalHourlyRate]

https://github.com/notro/gud/wiki/Gadget-Implementations mentioned old tablets/phones.

One way is to port f_gud to Android kernel, another way is to use mainline kernel with these old tablets/phones.

One implementation using postmarketOS is detailed in https://gist.github.com/ZenithalHourlyRate/220186818bae434386e80c62ee1bc7bc

[notro]

That's really cool and nice writeup!

I've added the link to the wiki page. The wiki should be writeable for all, so you can make the changes you want.

[notro]

I added a section in the wiki regarding your userspace implementation note: https://github.com/notro/gud/wiki/Gadget-Implementations#userspace-linux

[ZenithalHourlyRate]

That's really cool and nice writeup!

Thanks!

I've added the link to the wiki page. The wiki should be writeable for all, so you can make the changes you want.

I think I should notify you about the changes are to made.

[notro]

Made a short note in the wiki about buffer sharing which I guess is the problem with the Nvidia driver: https://github.com/notro/gud/wiki/Linux-Host-Driver#prime-buffer-sharing

Seems to be 2 problems:

1. The GUD driver uses the drm shmem helper and it doesn't support buffers that set map->is_iomem.
2. There's a bug somewhere that triggers a BUG_ON() in dma-buf. Probably an error path somewhere that doesn't clean up properly.

[ZenithalHourlyRate]

Made a short note in the wiki about buffer sharing which I guess is the problem with the Nvidia driver: https://github.com/notro/gud/wiki/Linux-Host-Driver#prime-buffer-sharing

Partial log for the host here (Repeated warnings ignored).

This happened when I unplugged GUD device from the host.

It seemds that the host can not find the buffer? Thus causing dma panic? Related line

gud 1-3:1.0: Failed to flush framebuffer: error=-5

[ZenithalHourlyRate]

Made a short note in the wiki about buffer sharing which I guess is the problem with the Nvidia driver: https://github.com/notro/gud/wiki/Linux-Host-Driver#prime-buffer-sharing

DRM PRIME Log here http://shz.al/xr7C. Generated by appending drm.debug=0x8 to kernel cmdline.

[notro]

Made a short note in the wiki about buffer sharing which I guess is the problem with the Nvidia driver: https://github.com/notro/gud/wiki/Linux-Host-Driver#prime-buffer-sharing

DRM PRIME Log here http://shz.al/xr7C. Generated by appending drm.debug=0x8 to kernel cmdline.

Looks like you forgot to plug in the USB display, there are no prime messages nor any splat.

[ZenithalHourlyRate]

Looks like you forgot to plug in the USB display, there are no prime messages nor any splat.

http://shz.al/P3SB. This time I booted up with GUD plugged in.