[Letux-kernel] [Gta04-owner] On camera driver

Andrey Utkin andrey_utkin at fastmail.com
Tue Aug 9 19:48:03 CEST 2016

On Tue, Aug 09, 2016 at 07:22:49PM +0200, H. Nikolaus Schaller wrote:
> Here is what it says w/o running any media-ctl before:

Maybe running it after media-ctl may give different results...

> Compliance test for device /dev/video0 (not using libv4l2):

Maybe other /dev/videoX devices should be tested (I've seen mention of

> So it is probed successfully on I2C but there is no /dev/media (if that is what should be looked for here)

Have never heard of /dev/media files, but i haven't worked with
media-ctl stuff yet.

> >> Hm. Running a GTA04 permanently on ssh is a little tricky. As soon
> >> as you poweroff it does not reboot automatically. And if you damage
> >> the SD card contents (a kernel panic during boot) it won't boot to USB
> >> without manually reflashing the SD card. So it needs supervision which
> >> I can't provide.
> > 
> > So "emergency reboot" like this doesn't reboot either?
> > 
> > sync
> > echo s > /proc/sysrq-trigger
> > sleep 1
> > echo b > /proc/sysrq-trigger
> How should that work if it does not boot up to an USB interface? How can
> we remotely issue such commands?

I meant to do this to get a proper reboot when we are fully booted,
replying to your statement "as you poweroff it does not reboot

> I mean the case that you did write a new uImage on the /boot partition
> or kernel module to /lib/modules over your ssh connection and then you do
> a reboot. But the uImage or some kernel module is broken now.

Nothing should be broken after "sync" command - it is supposed to flush
any disk caches.

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