Hi, I am working on adding AMD related drivers support for PCIe BARs move feature developed by Sergei (https://linuxplumbersconf.org/event/7/contributions/847/attachments/584/1035...). His feature is still not upstream, all his code and mine on top can be seen here - https://cgit.freedesktop.org/~agrodzov/linux/log/?h=yadro/pcie_hotplug/movab... I did basic implementation fro amdgpu driver and now I am doing the same for snd_hda_intel to support our on GPU Azalia audio chips. This relevant commit is here - https://cgit.freedesktop.org/~agrodzov/linux/commit/?h=yadro/pcie_hotplug/mo... Any driver that wants to support movable BARs needs to implement rescan_prepare, rescan_done and bar_fixed callbacks where rescan_prepare needs to stop HW/SW and unamp all MMIO mappings and rescan_done needs to ioremap the BAR from it's new MMIO location and restart HW/SW.
I am able currently to trigger BARs move by sysfs using "/sys/bus/pci/rescan" and the driver will go through the sequence I described above without hangs. Problem is that after this when i try to use mplayer I am getting following errors:
andrey@andrey-test:~$ sudo mplayer -ao alsa:device=hw=0.3 Downloads/file_example_MP3_5MG.mp3 MPlayer 1.3.0 (Debian), built with gcc-9 (C) 2000-2016 MPlayer Team do_connect: could not connect to socket connect: No such file or directory Failed to open LIRC support. You will not be able to use your remote control.
Playing Downloads/file_example_MP3_5MG.mp3. libavformat version 58.29.100 (external) Audio only file format detected. Load subtitles in Downloads/ ========================================================================== Opening audio decoder: [mpg123] MPEG 1.0/2.0/2.5 layers I, II, III AUDIO: 44100 Hz, 2 ch, s16le, 320.0 kbit/22.68% (ratio: 40000->176400) Selected audio codec: [mpg123] afm: mpg123 (MPEG 1.0/2.0/2.5 layers I, II, III) ========================================================================== AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample) Video: no video Starting playback... A: 0.1 (00.0) of 132.0 (02:12.0) ??,?% Audio device got stuck!
and in dmesg I see [ 365.355518] snd_hda_codec_hdmi hdaudioC0D0: Unable to sync register 0x2f0d00. -5
Also I see 296.619014] snd_hda_intel 0000:0a:00.1: CORB reset timeout#2, CORBRP = 65535 error during the rescan_done callback execution
I know it has to do with the move of BAR's MMIO address because when i disallow BAR migration by returning true from bar_fixed callback I have no such errors and mplayer works fine.
I enabled MMIO trace and didn't see that post BAR move there is a wrong MMIO access - all of them are from the new MMIO base offset - 0xfcd80000 (trace attached including mmio trace and dmesg)
I would be happy for any idea on this and any comment on the correctness of my sequence in the code
Andrey