Hi, On 12/26/20 3:28 PM, Hans de Goede wrote: > Hi All, > > On one of my machines I noticed the following errors being logged: > > [ 52.892807] i2c i2c-0: adapter quirk: no zero length (addr 0x0078, size 0, read) > [ 52.893037] i2c i2c-0: i2c read 0 bytes from client@0x78 starting at reg 0x0 failed, error: -95 > > The second line is coming from the Linux I2C ACPI OpRegion handling and > after a bunch of debugging I've found out that there is a rather obvious > (once you see it) and nasty race condition in the handling of I2C and GPIO > opregions in acpi_ev_address_space_dispatch(). See the first patch in this > series (the second patch is a follow-up cleanup patch removing some code > duplication). > > TBH I'm surprised that this issue has gone unnoticed as long as it has, > but I guess that it mostly leads to unreproducable sporadic problems > making it hard to debug and I got lucky that I had a machine where the > race seems to trigger about once every 20 seconds. > > I know that ACPICA patches are normally merged through the ACPICA upstream > but given that this is a serious bug, I believe that in this case it might > be best to add the fix directly to Linux and then port it to ACPICA from > there. ping ? This was submitted 2 full months ago; and despite this: 1. Fixing a serious bug in ACPICA 2. The fix being pretty simple (and AFAICT obviously correct) This is still awaiting review upstream: https://github.com/acpica/acpica/pull/658 I must say that it feels to me that the upstream ACPICA process is broken here. I submitted a pull-req for this, as requested and after that there has been zero progress. The pull-req even has a 26 day old "this looks good to me" comment from Erik, followed by silence... ? Rafael, can you please consider just directly picking these 2 fixes into your acpi branch, so that we can get this nasty race condition fixed ? Regards, Hans
