17.09.2014, 16:40, David Henningsson kirjoitti:
Hi,
Hi,
While investigating some interesting debug output from PulseAudio, I tried to figure out the cause.
From what I can tell, my Radeon seems to ask for new samples at a very high rate, which I estimate to be around 280 kHz. My radeon card has DVI, HDMI and VGA connectors, and the only thing connected is my screen over DVI.
I'm currently running the 3.13 kernel with updated hda directory from Takashi's tree, but I think it's been this way for a long time.
Note that if a screen is connected to the HDMI card, the problem disappears and sample rates are normal. In short, do you think this is a driver bug, or just something we have to live with as some sort of hw anomaly? Since nothing is connected, it does not really hurt, except PulseAudio gets confused (in a way that could potentially cause problems for low-latency output, should something be connected later on).
Not sure. IIRC, unlike the other gpus, on radeon the video driver needs to "manually" set sample rate dividers/etc based on the pixel clock rate, so I guess this might mean we can't have a proper audio clock without enabled video...
Alex, any thoughts/info?
If this is the case, it would probably be best if we prevented opening the device when output is not active (unless this causes some other issues), but I guess there is currently no easy way for the _audio_ driver to know that...
For reference, here's lspci of the HDMI card:
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] RV710 [Radeon HD 4550] [1002:9540] (prog-if 00 [VGA controller]) Subsystem: PC Partner Limited / Sapphire Technology Device [174b:e106] 01:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] RV710/730 HDMI Audio [Radeon HD 4000 series] [1002:aa38] Subsystem: PC Partner Limited / Sapphire Technology Device [174b:aa38]