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Currently quirks are only allowed for Slave devices. This patch describes the need for two quirks at the Master level. a) bus clash The SoundWire specification allows a Slave device to report a bus clash with the in-band interrupt mechanism when it detects a conflict while driving a bitSlot it owns. This can be a symptom of an electrical conflict or a programming error, and it's vital to detect reliably. Unfortunately, on some platforms, bus clashes are randomly reported by Slave devices after a bus reset, with an interrupt status set even before the bus clash interrupt is enabled. These initial spurious interrupts are not relevant and should optionally be filtered out, while leaving the interrupt mechanism enabled to detect 'true' issues. This patch suggests the addition of a Master level quirk to discard such interrupts. The quirk should in theory have been added at the Slave level, but since the problem was detected with different generations of Slave devices it's hard to point to a specific IP. The problem might also be board-dependent and hence dealing with a Master quirk is simpler. b) parity Additional tests on a new platform with the Maxim 98373 amplifier showed a rare case where the parity interrupt is also thrown on startup, at the same time as bus clashes. This issue only seems to happen infrequently and was only observed during suspend-resume stress tests while audio is streaming. We could make the problem go away by adding a Slave-level quirk, but there is no evidence that the issue is actually a Slave problem: the parity is provided by the Master, which could also set an invalid parity in corner cases. BugLink: https://github.com/thesofproject/linux/issues/2578 BugLink: https://github.com/thesofproject/linux/issues/2533 Co-developed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com> Link: https://lore.kernel.org/r/20210302082720.12322-2-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> |
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| linux | ||
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| sound | ||
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