OMAPDSS: omap5 SYNC_LOST error with DPI/LCD

Vikas Patil vikasmpatil at
Mon May 12 23:26:55 PDT 2014

Hi Tomi,

>That driver cannot be used with omapdrm, which uses omapdss. There's no
TDF19988 driver for omapdss (at least in the mainline),
Just to better understand, could you please explain why I can't use it with
omadrm and omapdss? Which scenario this driver will be useful?  I think I
still didn't understand how all this sit together.

Do you think following driver can be used as a reference to start? (Sil9022 DPI to HDMI

Thanks for sparing your valuable time here.


On Mon, May 12, 2014 at 6:01 PM, Vikas Patil <vikasmpatil at> wrote:

> Hi Tomi,
> Thank a lot  for your inputs and patch info.
> It seems I cannot apply those patches straight away as it is based on
> 3.6-rc4 and I am using 3.4.25, between these two, it seems significant code
> changes for DSS related code.
> I am using 3.4.25 kernel from TI for OMAP5 evm, it has been modified as
> per our platform requirement which is having OMAP5 ES2.0 revision.
> I am trying to use the panel driver for DPI interface(i.e.
> Kernel\drivers\video\omap2\displays\panel-generic-dpi.c). So DSS and panel
> driver path are as follows
> Kernel\drivers\video\omap2\dss\dpi.c,dss.c,display.c,dss_features.c etc
> Kernel\drivers\video\omap2\displays\panel-generic-dpi.c
> soc specific:
> Kernel\arch\arm\mach-omap2\omap5_es2\clkt_clksel.c,
> clkt_dpll.c,clock.c,cm44xx_54xx.c etc
> omapdrm path:
> Kernel\drivers\staging\omapdrm
> In case for working HDMI port, we are using:
> Kernel\drivers\video\omap2\dss\hdmi.c
> Kernel\drivers\video\omap2\dss\hdmi_panel.c
> I think this would require considerable amount of understanding on dss
> architecture and effort to backport some of the things, write new driver
> fro TDF19988 and make DPI interface working for our platform for someone
> like me who has just started working on DSS/Display.
> Regards,
> Vikash
> On Mon, May 12, 2014 at 5:28 PM, Tomi Valkeinen <tomi.valkeinen at>wrote:
>> On 12/05/14 14:33, Vikas Patil wrote:
>> > Hi,
>> >
>> > Re-posting as previous posting was rejected due to length.
>> >
>> > Forgot to mention, DPI pins are connected to TDF19988 chip for HDMI
>> > conversion.
>> > I have build the driver for it from
>> >
>> .
>> > Is this the correct driver for it?
>> That driver cannot be used with omapdrm, which uses omapdss. There's no
>> TDF19988 driver for omapdss (at least in the mainline), so you need to
>> write one.
>> > Also I am trying to use the generic-dpi-panel driver for this with
>> > OMAP5. It seems I also need to add support for TDF19988 somewhere in
>> > omapdrm or lcd/panel driver by calling drm_i2c_encoder_init to
>> > initialize it. Can I use somecode from ticldc driver or driver itself?
>> > Could you please give some inputs, how should I proceed further to
>> > adding support for TDF19988 for which the input is coming from DPI
>> > interface?
>> You need to write a driver for it. Something similar to
>> drivers/video/fbdev/omap2/displays-new/encoder-tfp410.c, except tfp410
>> is quite simple one.
>> But I think you said you're based on some old customized kernel, so I
>> don't know which kind of omapdss driver you have there, so the mainline
>> tfp410 cannot probably be used as an example. Most likely the omapdss
>> drivers for your kernel are located in drivers/video/omap2/displays/
>> directory.
>>  Tomi
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the dri-devel mailing list