On Wed, Sep 14, 2022 at 03:15:52PM +0100, Maciej W. Rozycki wrote: > On Wed, 14 Sep 2022, Maciej W. Rozycki wrote: > > > I'll examine your I/O conversation log in detail and will see if I can > > come up with a possible explanation. > > I think I know what is going on here. Can you please confirm that you > have the CONFIG_SERIAL_8250_16550A_VARIANTS option disabled (default to > "off" for x86 only)? That would explain things. > > Offhand I am not sure what to do here. There are several options to > choose from I can think of right now: > > 1. Disable new OxSemi Tornado clock code iff !SERIAL_8250_16550A_VARIANTS, > bringing back buggy calculation for rates above 115200bps and coarse > BOTHER granularity. > > 2. Same as above, but additionally limit the baud rates to 115200bps to > avoid buggy rates. Maybe this one? That feels odd that we do different things for this old config option, that's not good. So making this "just work" should be the best idea if at all possible. > > 3. Force SERIAL_8250_16550A_VARIANTS to "y" if SERIAL_8250_PCI != "n". > > 4. Remove SERIAL_8250_16550A_VARIANTS altogether and execute code it > guards unconditionally (does it still matter nowadays?). > > 5. Something else not yet determined. We can't just remove it, as for x86 the default is disabled due to this only being relevant for very old hardware. thanks, greg k-h
