On Wed, Sep 04, 2024 at 18:27:00PM +0000, Mark Brown wrote: > On Wed, Sep 04, 2024 at 02:46:30PM +0100, Simon Trimmer wrote: > > On Wed, Sep 04, 2024 at 12:25:00PM +0000, Mark Brown wrote: > > > On Wed, Sep 04, 2024 at 12:07:00PM +0000, Simon Trimmer wrote: > > > > > The IRQ handling in the cs35l56 driver was purely informational. It was > > > > not necessary to support the HDA or ASoC driver functionality and added > > > > unnecessary complexity to the drivers. > > > > Given that the code is there now and has been since the driver was > > > introduced about 18 months ago what's the ongoing cost of having it? > > > The information it's providing is notification of hardware faults, > > > reporting those does seem useful. > > > Originally we were expecting to use the IRQ mechanism for an event logging > > stream that would function in a similar manner to compressed streams to be > > able to get an information feed for debug and tuning tools, but those were > > never created and the logging infrastructure not implemented. > > Right. Though ideally we might actually do something about some of > the errors that are reported. > > > It's quite a spread of code and a lot of complexity in the regular execution > > paths managing them / synchronizing the contexts, there is more going on in > > the SoundWire bus variant compared to the conventional i2c/spi that it is > > hard to justify maintaining it all for a couple of log messages - in the > > event that someone did encounter the two situations being reported the > > regmap dump would point us to the cause pretty quickly. > > I'm not sure how many end users are going to get as far as talking to > you in the event that they have issues - people often won't get as far > as trying to contact their distros or upstreams. Even errors in dmesg > are pretty obscure but they're more discoverable than interpreting the > regmap, people would need to identify that they need to look at the chip > first and actually be experiencing the problem when they figure that > out. Ideally we'd hae better handling for this (I did note that the > latest Iron Devices driver will back off speaker volume during a thermal > warning which isn't a terrible idea, though there's potential issues). I'll have a chat to people when they are back at work - the IRQ signals we were logging were from the firmware rather than the hardware as it entered a protection state, this isn't fatal and can clear. Over the last few years I don't think I've encountered them in testing except for when I deliberately abused the hardware which I don't think anyone would recommend :) How people behave when encountering trouble is certainly true - as more PCs adopt our devices we have a steadily increasing stream of direct support messages and have been getting tagged in distro issue reports. These have been universally around missing support in particular kernel versions or the linux-firmware package not containing the necessary tuning files, so far I've only asked our field/partner engineers for a dump of a regmap and I've not seen a report of a hardware warning yet but I too suspect these are the tip of the iceberg for people encountering troubles. A general Linux tangent - we had been debating how many of our end users multiboot their hardware vs those who just run Linux on them - has anyone seen any reports or statistics in this area? > It sounds like the only real concern is the Soundwire stuff (I2C and SPI > interrupt stuff should generally be trivial?) - if that's the case I'd > be more inclined to only pull out the Soundwire bits and leave the > support there for the simpler buses. That is a good idea and would certainly make things better - I'll see what I can do -Simon
