Adjusting memory speed according to display

[Deucher, Alexander]

You have to set up the display to send audio data over HDMI.  The audio is embedded in the stream.  You have to set up the video stream to use audio.  You need to raise the memory clocks to provide the necessary bandwidth for multiple display and dynamic mclk switching is not supported with multiple displays enabled because the switches are done during the vertical blanking period.  If you have multiple displays with different timing, the blanking periods do not match so glitch free switching is not possible.

If you want more control, you can use the sysfs files to either manually force the clocks low or high or manually  enable only specific clock levels for sclk and mclk.

Alex

From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf Of Jarkko Korpi
Sent: Thursday, August 11, 2016 9:45 PM
To: amd-gfx at lists.freedesktop.org
Subject: Adjusting memory speed according to display


I have rx480 which I connect into 1920x1080 pc screen via DP and audio into external amplifier via HDMI. This causes rx480 to raise the memory speed to 2000 while doing really simple tasks like watching youtube. I really dont need thatkind of speed for memory. And I am not aware that it's possible to change between 300mhz 2000mhz memory speeds, but gpu supports this in steps which would be really great for memory too. I only need the audio data submited to the amplifier. Is it possible somehow to form a patch that it somehow recognizes my amplifier and understands that I am sending audio that I dont need/want it to max the memory speed? I would be really happy for such patch for personal use. If it's too hacky to be merged into upstream.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20160812/bf16901b/attachment.html>