Well, it's still not clear who to blame. Practically seen, the problem
appears on a certain Realtek codecs just because there are such codec
chips on the market for major mobos. Except for a few vendors (like
Apple), all boards are equipped with Realtek codecs. So, I still
suspect the problem being in HD-audio controller -- the AMD chipset
side.
Can people check whether any of workarounds have any effect? For
example,
- Make sure the existing quirks for ATI boards:
Check the PCI device ID of your HD-audio controller connected to the onboard
analog audio. You may have multiple HD-audio controller entries, and one of
them is for HDMI and another for the onboard audio.
The table in sound/pci/hda/hda_intel.c indicates the type and the quirk. The
AMD one should be with AZX_DCAPS_PRESET_ATI_SB.
- Disable the page caching.
This can be done by passing snoop=0 option. But maybe it's more interesting
to forcibly disable the cache while keeping the PCI snoop enabled, e.g. apply a
patch like:
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1681,6 +1681,7 @@ static int azx_create(struct snd_card *card, struct
pci_dev *pci,
chip->single_cmd = single_cmd;
azx_check_snoop_available(chip);
+ chip->uc_buffer = true; // XXX
if (bdl_pos_adj[dev] < 0)
- Adjust more quirk bits:
AZX_DCAPS_PRESET_ATI_SB contains AZX_DCAPS_NO_TCSL. Try to remove this flag,
for example.
Also, add more flags, e.g. AZX_DCAPS_NO_MSI, AZX_DCAPS_NO_MSI64,
AZX_DCAPS_NO_64BIT, AZX_DCAPS_4K-BDLE_BOUNDARY.
- Try different sample rates, format, period and buffer sizes:
At best test with aplay / arecord with -Dhw option to skip pulseaudio.
(You can run it over pasuspender.)
Check various parameters, e.g. 44.1k vs 48kHz, S16_LE vs S32_LE. Try to
align the period size and the buffer size to be 4kB.
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https://bugs.launchpad.net/bugs/1801540
Title:
Microphone distorted sound on ALC892/1220 on AMD chipsets
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