[Intel-gfx] [BUG] HDMI 12bpc causing occasional flickering and blanking

[Ville Syrjälä]

On Wed, Feb 24, 2016 at 06:48:35PM +0100, Tore Anderson wrote:
> Hi Ville,
> 
> > Well, just to check the details of your particular cable/dongle,
> > maybe you can post the dmesg with drm.debug=0xe with my branch?
> > Or at least the parts that refer to DP dual mode adaptors.
> 
> Here: http://filebin.net/gd91wnltky/dmesg.4.5.0-rc4-g32fa589.txt
> 
> I'm assuming the most important parts are:
> 
> [drm:intel_hdmi_dp_dual_mode_detect] DP dual mode adaptor (type 1 HDMI) detected (max TMDS clock: 165000 kHz, TMDS OE# control: no)
> [drm:intel_hdmi_compute_config] picking bpc to 8 for HDMI output
> 
> For the record, I'd call my adapter a «cable» and not a «dongle». I had
> thought it was completely passive; if there's any active circuitry
> inside it it must be really tiny - it'd have to fit inside the rather
> standard-sized HDMI/DP connectors in the ends.

Yeah, the chips used for this stuff are pretty small. I had one dongle
fry itself a while back, so I pulled it apart and found a PS8121E
chip inside it (with a number of other mostly passive components).

-- 
Ville Syrjälä
Intel OTC