We've been busy implementing ACPI 6.4 support in ACPICA. Sorry for the delay. Bob -----Original Message----- From: Rafael J. Wysocki <rafael@xxxxxxxxxx> Sent: Monday, February 15, 2021 10:26 AM To: Hans de Goede <hdegoede@xxxxxxxxxx> Cc: Rafael J . Wysocki <rjw@xxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; Moore, Robert <robert.moore@xxxxxxxxx>; Kaneda, Erik <erik.kaneda@xxxxxxxxx>; ACPI Devel Maling List <linux-acpi@xxxxxxxxxxxxxxx>; open list:ACPI COMPONENT ARCHITECTURE (ACPICA) <devel@xxxxxxxxxx> Subject: Re: [PATCH 0/2] ACPICA: Fix a race in GenericSerialBus (I2C) and GPIO handling On Mon, Feb 15, 2021 at 6:52 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > 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 ? I will do that later this week, thanks!
