ATI oss color space compressed in the dark shades of gray

[Alex Deucher]

On Fri, Mar 14, 2014 at 9:26 AM, Alex Deucher <alexdeucher at gmail.com> wrote:
> On Thu, Mar 13, 2014 at 6:34 AM, Sebastian Schultz
> <sebastian2.schultz at st.ovgu.de> wrote:
>> Is there anything I can do to about it? Or is this an upcoming feature? Or is
>> it a bug and I should submit a report?
>
> It would be a new feature.  It's not a high priority at the moment, so
> I'm not sure how quickly we would get to it.

If you are inclined to play with this yourself, try adjusting the
registers in dce5_crtc_load_lut(), in particular
NI_OUTPUT_CSC_CONTROL.NI_OUTPUT_CSC_GRPH_MODE.  Try setting it to
NI_OUTPUT_CSC_TV_RGB or NI_OUTPUT_CSC_YCBCR_601 or
NI_OUTPUT_CSC_YCBCR_709.

Alex

>
> Alex
>
>>
>> Sebastian
>>
>>
>> Am Mittwoch, 12. März 2014, 12:18:37 schrieb Alex Deucher:
>>> On Wed, Mar 12, 2014 at 10:31 AM, Sebastian Schultz
>>>
>>> <sebastian2.schultz at st.ovgu.de> wrote:
>>> > Hello,
>>> >
>>> > first of all: I'm using a Radeon 7750 in combination with a monitor via
>>> > display port and a tv via the HDMI port. Most of the time I do not want a
>>> > picture on the tv, only when wathcing videos, so I use xrandr scripts to
>>> > switch that display on and off. And here comes my problem:
>>> >
>>> > With the arrival of linux 3.13 to the [core]-repo of arch linux I switched
>>> > from catalyst to the open source drivers, as they finally provide a
>>> > sufficient performance. My only problem now is that the colorspace is
>>> > compressed for gray values below 16 (that means every shade of gray
>>> > having values of 0 to 16 look just black). That's only the case for my
>>> > HDMI-output connected to my TV, which worked without problems with the
>>> > catalyst drivers. Also, only the dark grays are compressed, the
>>> > near-white grays show up correct.  My Xorg.0.log shows that the TV on
>>> > HDMI-0 supports the RGB 4:4:4 encoding (just like the monitor does):
>>> > http://pastebin.com/PF6sjzu1
>>> >
>>> > I found a xrandr-command "--set "Broadcast RGB" "Full"", which can be used
>>> > with chips from Intel. Is there something similar for the open source ati
>>> > drivers?
>>>
>>> Not at the moment.
>>>
>>> Alex
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