HDMI: Image on TV too dark

[Alex Deucher]

On Thu, Oct 13, 2011 at 6:40 AM, Frederik Vogelsang
<frederik.vogelsang at googlemail.com> wrote:
> 2011/10/12 Alex Deucher <alexdeucher at gmail.com>:
>> If it's movies, you might need to adjust the Xv attributes
>> (brightness, contrast, saturation, hue, colorspace, etc.) if you are
>> using Xv.  Your movie player may have an interface to adjust them, if
>> not, try something like xvattr.
> No, it is not just related to movies/xv. This also applies to normal
> desktop usage. It is also impossible to view some darker images from
> my digital camera on my TV without using the xcalib command I posted
> earlier. It is definitely not related to a TV setting  - viewing the
> same images directly on the TV (through the SD card slot) they look
> just fine - only when viewing them through the PC they are too dark.
>
> Any other ideas on how to get around the xcalib "hack"? How is the
> brightness for a digital output set anyway? Is it calculated
> dynamically? Does it have anything to do with the EDID?

The brightness is set on the TV itself.  The only thing the driver can
really adjust is the gamma correction which is exposed via xrandr or
xgamma if you want to adjust it.  You might try connecting directly to
the TV as Andy suggested, or try booting with radeon.audio=0 depending
on how old your kernel is.

Alex