No display for running framebuffer.run

Stefan Kalkowski stefan.kalkowski at ...1...
Wed Mar 12 16:06:47 CET 2014 

Hi,

On 03/12/2014 01:10 PM, Aditya Kousik wrote:
> Hi Stefan,
> 
> On 12 Mar 2014 16:47, "Stefan Kalkowski" 
> <stefan.kalkowski at ...1...> wrote:
>> 
>> Hi Aditya,
>> 
>> the framebuffer driver for Freescale's IPUv3 device is expected 
>> to work out of the box when using the i.MX53 SABRE tablet, as 
>> well as the i.MX53 Quickstart Board. Both configurations work 
>> with statically assigned resolutions.
>> 
>> To let it work on your concrete i.MX6 board, you've to adapt the 
>> driver code to use appropriated DMA channels, correct timings,
>> as well as an appropriated resolution. Moreover, typically you've
>> to do something to enable the display, like GPIO + IOMUX
>> controller routings, which is done for the mentioned boards in
>> the platform driver of Genode.
> 
> Yes, even I'm using the Linux and u-boot driver routines as base. 
> And your exquisite version for the i.mx53 as reference. The 
> initialisation routine for i.mx6 though similar, is not entirely 
> same. The CCM defs and protocols are a bit different since I.MX6 
> has two IPU units.
>> 
>> I'm afraid, I can't help you with an easy way to debug it. When 
>> doing the same work for e.g. the SABRE tablet, I've traced the 
>> available Linux driver to find out, what needs to be done in 
>> general. I'm afraid the documentation, although substantial with 
>> respect to register definitions, isn't sufficient to build it 
>> from scratch.
>> 
> 
> And as far as IOMUXC+GPIO pads are concerned, we've written a
> macro that sets the display on (though it's unclear as to which pin
> to set to do that). We first wrote the macro in the driver space 
> itself, but Genode's excellent RM service threw a faulted error.
> So as a ready-reckoner, put the code at kernel level. No positive 
> result, unfortunately.
> 

It sounds to me, like you were using the physical address of the
memory mapped I/O regions for the corresponding devices, if you were
experiencing pagefaults in the (userland) drivers, but not in the
kernel, where the physical memory is mapped 1:1 to virtual memory
currently. Instead of putting the initialization into the kernel, you
should use the virtual address you're gaining after you attached the
I/O memory dataspace to the driver's region manager session.

>> Of course there are other run scripts that make use of the 
>> framebuffer, like for instance 'os/run/demo.run'.
>> 
>> Regards Stefan
>> 
> 
> Can you shed some light on why the following exception is thrown? 
> "C++ runtime: Genode::Parent::Service_denied". I tried running the 
> nitpicker test directly and the service goes to abort() from the 
> boot_modules.
> 
> Best, Aditya.

That means one application, in this case probably the nitpicker test
application, tried to get access to some service, and its parent, or
one of its grandparents didn't found an appropriated route to such
service. I assume, you have added the nitpicker test application, but
not the nitpicker server itself, or did some other misconfiguration.
I strongly advise to first read how init's configuration works in
depth (e.g.: 'os/doc/init.txt'), before changing its configuration.
Please feel free to ask specific questions related to configuration
issues, but consider to include the complete configuration, or at
least modifications you've done.

Regards
Stefan

> 
>> On 03/12/2014 11:52 AM, Aditya Kousik wrote:
>>> Hi Christian,
>>> 
>>> We're basically running tests for our framebuffer driver on
>>> our Genode
> port
>>> for i.MX6 board. Similar results. No concrete display on the 
>>> LVDS
> display.
>>> The screen gets pixelated gradually from black to complete 
>>> white. While this could be a fault with the driver, it'll
>>> still be good to know how
> to
>>> debug it. What ARM board did you carry out your experiments 
>>> with?
>>> 
>>> Also, are there other run scripts to test framebuffer?
>>> 
>>> ---- Aditya.
>>> 
>>> 
>>> On Wed, Mar 12, 2014 at 4:12 PM, Christian Helmuth < 
>>> christian.helmuth at ...1...> wrote:
>>> 
>>>> Hello Aditya,
>>>> 
>>>> it seems you discovered a bug in the framebuffer test.
>>>> 
>>>> On Wed, Mar 12, 2014 at 03:50:14PM +0530, Aditya Kousik 
>>>> wrote:
>>>>> I've tried running the test-framebuffer on my linux_x86 
>>>>> base. The
>>>> terminal
>>>>> log session sends debug message of "blue", "green", "red" 
>>>>> etc. But
>>>> nothing
>>>>> shows on the QEMU monitor. What could be going wrong here?
>>>> 
>>>> I opened issue #1092 on Github for tracking developments. 
>>>> Please feel invited to investigate further on the issue and 
>>>> discuss your findings under
>>>> 
>>>> https://github.com/genodelabs/genode/issues/1092
>>>> 
>>>> Regards -- Christian Helmuth Genode Labs
>>>> 
>>>> http://www.genode-labs.com/ · http://genode.org/ 
>>>> https://twitter.com/GenodeLabs · /ˈdʒiː.nəʊd/
>>>> 
>>>> Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz 
>>>> Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian 
>>>> Helmuth
>>>> 
>>>> 
>>>> 
> ------------------------------------------------------------------------------
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>>> 
>>> 
>>> 
>>> 
> ------------------------------------------------------------------------------
>>>
>
> 
Learn Graph Databases - Download FREE O'Reilly Book
>>> "Graph Databases" is the definitive new guide to graph 
>>> databases and
> their
>>> applications. Written by three acclaimed leaders in the field,
>>>  this first edition is now available. Download your free book 
>>> today! http://p.sf.net/sfu/13534_NeoTech
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>> 
>> -- Stefan Kalkowski Genode Labs
>> 
>> http://www.genode-labs.com/ · http://genode.org/
>> 
>> 
> ------------------------------------------------------------------------------
>>
>
> 
Learn Graph Databases - Download FREE O'Reilly Book
>> "Graph Databases" is the definitive new guide to graph databases 
>> and their applications. Written by three acclaimed leaders in
>> the field, this first edition is now available. Download your
>> free book today! http://p.sf.net/sfu/13534_NeoTech 
>> _______________________________________________ Genode-main 
>> mailing list Genode-main at lists.sourceforge.net 
>> https://lists.sourceforge.net/lists/listinfo/genode-main
> 
> 
> 
> ------------------------------------------------------------------------------
>
>
> 
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> "Graph Databases" is the definitive new guide to graph databases 
> and their applications. Written by three acclaimed leaders in the 
> field, this first edition is now available. Download your free
> book today! http://p.sf.net/sfu/13534_NeoTech
> 
> 
> 
> _______________________________________________ Genode-main
> mailing list Genode-main at lists.sourceforge.net 
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-- 
Stefan Kalkowski
Genode Labs

http://www.genode-labs.com/ · http://genode.org/

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