Hello Jan,
Only generic advice for debugging kernel modules I'm afraid: for a start
set up a serial console (or use VirtualBox logging to the host<1>) and
put log statements in the paths which are getting triggered to
understand what is happening and where things hang; and/or use ftrace to
see what is getting called.
Regards,
Michael
<1> https://www.virtualbox.org/wiki/VBoxLogging
On 14.09.2016 12:06, Jan Petrouš wrote:
Hi Michael.
On 6 September 2016 at 11:13, Michael Thayer
<michael.tha...@oracle.com <mailto:michael.tha...@oracle.com>> wrote:
>
> Hello Jan,
>
> I think you asked about this on IRC yesterday. The first file that
you mention is part of the Linux drm driver (the rest is the other files
in that folder). I wrote the driver, based on in-kernel ones, but I am
not an expert in the kernel drm subsystem, and in particular I only use
the basic kernel fbdev translation functions to provide the framebuffer
driver. You would probably be better asking on the dri-devel list<1>
about what to change to get one fbdev device per head. You might be in
luck and there might be a simple solution.
>
I just get some patches which adds to the linux vboxvideo.ko support for
multiframebuffer (one framebuffer per display).
But I have some very strange trouble with it.
When started, only the first framebuffer is working (and so only one
graphical display is enabled).
Then I enable second FB by entering "fbset -ifb /dev/fb1 -accel 1".
An that moment, I get the virtual machine freezed. Now if I try to send
[ENTER] or any other key,
I don't see cursor or any ather activities on the command line (on guest
Linux system).
The strangeness is that if I click on close button of guest console
window (so the popup menu starts
with option of save, shutdown or power-off), the windows title changed
to "paused" and only now I can see
the previously entered keys showed on guest console. It looks like
console lock is released when
popup windows started and again acquired if I cancel popup.
It looks like the guest console (fbcon?) gets freezed (so locked) by
some initialization task inside
the modified vboxvideo driver.
Configuration:
Host system: Fedora 24 desktop with kernel 4.6.7, but my colleague tries
that on Windows 7, the issue is the same,
so I guess it is host system independetend issue
Guest: I tried two distros, both have installed minimal packages and no Xwin
Guest1: Fedora 24 desktop, kernel 4.6.7
Guest2: Arch latest, kernel 4.7.2
Do you have any idea how to debug such console freeze?
/Jan
Yes, I was asking on irc, but I think I fallen in lunch mode there, so
only silence :)
That is why I asked here again.
Anyway, thanks for the hints! I definitely will have a try with drm.
But it's good that the author of driver is reachable.
So more questions can come later ;)
CU
/Jan
> Regards,
>
> Michael
>
> <1> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>
> On 05.09.2016 17:42, Jan Petrouš wrote:
>>
>> Hi,
>>
>> as VirtualBox supports dual head config I was trying to start two
>> framebuffers on it.
>> But unsucessfull.
>>
>> The main constraint is that guest Linux is very tiny and has no
>> X-Windows inside.
>> The application requires only the framebuffer devices.
>>
>> I did many hours googling to find solution but I found only
solution for
>> xwin environment.
>>
>> Is it even possible to enable two FB devices on dualhead configuration?
>>
>> If the answer is NO, can you show me where I should start to look
inside
>> the sources?
>>
>> I found the VB Additions subversion repo where are at least two video
>> drivers:
>>
>> 1,
>>
http://www.virtualbox.org/svn/vbox/trunk/src/VBox/Additions/linux/drm/vbox_fb.c
>> 2,
>>
http://www.virtualbox.org/svn/vbox/trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c
>>
>> I guess that the driver for my non-x11 environment is the first one. Is
>> it true?
>>
>> I'm rather linux video driver noob, but I would like to get some good
>> start point
>> where I can at least try to start with.
>>
>> BR.
>> /Jan
>>
>> PS: Installed Fedora Server 24 Minimal config, so kernel is 4.6.7
>>
>>
>> _______________________________________________
>> vbox-dev mailing list
>> vbox-dev@virtualbox.org <mailto:vbox-dev@virtualbox.org>
>> https://www.virtualbox.org/mailman/listinfo/vbox-dev
>>
>
> --
> Michael Thayer | VirtualBox engineer
> ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | D-71384 Weinstadt
>
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>
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--
Michael Thayer | VirtualBox engineer
ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | D-71384 Weinstadt
ORACLE Deutschland B.V. & Co. KG
Hauptverwaltung: Riesstraße 25, D-80992 München
Registergericht: Amtsgericht München, HRA 95603
Komplementärin: ORACLE Deutschland Verwaltung B.V.
Hertogswetering 163/167, 3543 AS Utrecht, Niederlande Handelsregister
der Handelskammer Midden-Nederland, Nr. 30143697
Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher
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