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I get a blank screen when trying to boot unless I set 'radeon.dpm=0' in my kernel parameterts. Might seem like a fix, but I want dpm to be enabled and I can't figure out what's going on. The card is an r7 370. Any ideas?
edit:
a bit of progress. If I enable a quiet boot, I can get all the way through logging in before the screen goes blank, although stuff flickers a bit. So, this tells me that dpm isn't just completely failing immediately, but is failing after some use. If I disable early kms-start, I can get even further, log in and use it for quite a few commands before things fail. Running "clear" invariably causes the screen to go black and not return. Looking at boot logs with journalctl, there are no errors relating to radeon or dpm (there are actually no errors at all, at least nothing with the word "ERROR" in it, and I went through the entire log for a boot with dpm enabled and didn't see anything that looked out of the ordinary). It's loading dpm and even setting a power profile for the card. This all successfully happens /before/ things go bad, the screen goes blank, and nothing works. I haven't been able to find any logs from when that happens that might explain it.
For reference, the reason I want dpm enabled is that it improves performance significantly, or, at least, did with my old card (RIP) running radeon.
Last edited by davidjosepha (2016-08-11 16:12:43)
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In a stroke of brilliance I didn't think myself capable of, I decided that maybe it was a power issue. And, so I set KMS to late-start and wrote a one time script to run at boot to set /sys/class/drm/card0/device/power_dpm_force_performance_level to low. And... the boot worked fine, dmesg confirms that dpm started properly. If I try a similar thing but setting it to high instead of low, the card fails as usual. So, I guess, there's something going wrong with the high, and I think it's that it's trying to draw more power than it's capable of, and so, the card is failing. But that might be entirely wrong.
Edit: I think I've confirmed that it's related specifically to this, because with dpm disabled, I was able to reproduce the problem with
echo high > /sys/class/drm/card0/device/power_profilealthough "low" and "mid" work fine. So, basically, it's not an issue with dpm specifically, it's an issue with my card when it's set to a high frequency/voltage. Could this be an issue with the card itself? Seems like not, it's brand new and seems to work fine except in these cases. Something with my motherboard? I've already checked physically that the card is completely connected and power cables plugged in, but maybe something in the BIOS?
Last edited by davidjosepha (2016-08-12 15:13:52)
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