BBB Framebuffer : Need Ideas.
Vijay Kumar Banerjee
vijaykumar9597 at gmail.com
Wed Jul 10 10:38:20 UTC 2019
On Wed, Jul 10, 2019 at 12:40 PM Christian Mauderer <
christian.mauderer at embedded-brains.de> wrote:
> On 09/07/2019 21:13, Vijay Kumar Banerjee wrote:
> > Hello all,
> > First the status :
> > * The fbd has been ported and it's attaching with the fb0 devie. There's
> > an fb0 device entry created.
> > * In the following commit I have added mmap to libbsd. This works like a
> > wrapper to the mmap in cpukit
> > :
> > Blocker :
> > * After the fb0 is created and mmap is added, I don't see anything on
> > the screen. From the FreeBSD, it seemed like the VT driver is needed
> > and that is responsible for turning on the screen. So I have ported a
> > minimal version of the VT with only the initialization and allocate
> > But even after porting the VT driver which initializes well ( As the
> > message during booting says). I don't see anything on the screen.
> > I need some ideas on what is missing or how to debug this.
> > The app I'm using to test framebuffer is pushed here :
> > https://github.com/thelunatic/rtems-bbb/tree/master/apps/fb-sample
> > Any idea regarding this is greatly appreciated.
> > Thanks,
> > Vijay
> Hello Vijay,
> did you have a look at the SPI of the HDMI framer? What is it used for
> according to the data sheet? Is it necessary for the driver?
>From the datasheet, it seems that the SPI1_CS0 and SPI1_D0 pins are
configured as I2S interface for the audio. I think this is not necessary
and it is enabled only for a few selected resolutions that support audio.
> From our chat discussions and my own tests I know that the screen is
> still not receiving a signal. So I would assume some quite basic
> problem. If your new mmap wouldn't work, you should still get at least a
> black screen.
> I was also hoping that VT will do the initialization and turn the screen
There might be something useful that I omitted during the porting. If you
can please review the commit, I can send it in the devel.
> Best regards
> embedded brains GmbH
> Herr Christian Mauderer
> Dornierstr. 4
> D-82178 Puchheim
> email: christian.mauderer at embedded-brains.de
> Phone: +49-89-18 94 741 - 18
> Fax: +49-89-18 94 741 - 08
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> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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