On Sun, Mar 09, 2025 at 11:46:43PM +0300, Fedor Pchelkin wrote:
> On Wed, 19. Feb 15:20, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
> >
> > This is a note to let you know that I've just added the patch titled
> >
> > acpi: typec: ucsi: Introduce a ->poll_cci method
> >
> > to my usb git tree which can be found at
> > git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
> > in the usb-linus branch.
> >
> > The patch will show up in the next release of the linux-next tree
> > (usually sometime within the next 24 hours during the week.)
> >
> > The patch will hopefully also be merged in Linus's tree for the
> > next -rc kernel release.
> >
> > If you have any questions about this process, please let me know.
> >
> >
> > From 976e7e9bdc7719a023a4ecccd2e3daec9ab20a40 Mon Sep 17 00:00:00 2001
> > From: "Christian A. Ehrhardt" <lk@xxxxxxx>
> > Date: Mon, 17 Feb 2025 13:54:39 +0300
> > Subject: acpi: typec: ucsi: Introduce a ->poll_cci method
> >
> > For the ACPI backend of UCSI the UCSI "registers" are just a memory copy
> > of the register values in an opregion. The ACPI implementation in the
> > BIOS ensures that the opregion contents are synced to the embedded
> > controller and it ensures that the registers (in particular CCI) are
> > synced back to the opregion on notifications. While there is an ACPI call
> > that syncs the actual registers to the opregion there is rarely a need to
> > do this and on some ACPI implementations it actually breaks in various
> > interesting ways.
> >
> > The only reason to force a sync from the embedded controller is to poll
> > CCI while notifications are disabled. Only the ucsi core knows if this
> > is the case and guessing based on the current command is suboptimal, i.e.
> > leading to the following spurious assertion splat:
> >
> > WARNING: CPU: 3 PID: 76 at drivers/usb/typec/ucsi/ucsi.c:1388 ucsi_reset_ppm+0x1b4/0x1c0 [typec_ucsi]
> > CPU: 3 UID: 0 PID: 76 Comm: kworker/3:0 Not tainted 6.12.11-200.fc41.x86_64 #1
> > Hardware name: LENOVO 21D0/LNVNB161216, BIOS J6CN45WW 03/17/2023
> > Workqueue: events_long ucsi_init_work [typec_ucsi]
> > RIP: 0010:ucsi_reset_ppm+0x1b4/0x1c0 [typec_ucsi]
> > Call Trace:
> > <TASK>
> > ucsi_init_work+0x3c/0xac0 [typec_ucsi]
> > process_one_work+0x179/0x330
> > worker_thread+0x252/0x390
> > kthread+0xd2/0x100
> > ret_from_fork+0x34/0x50
> > ret_from_fork_asm+0x1a/0x30
> > </TASK>
> >
> > Thus introduce a ->poll_cci() method that works like ->read_cci() with an
> > additional forced sync and document that this should be used when polling
> > with notifications disabled. For all other backends that presumably don't
> > have this issue use the same implementation for both methods.
> >
> > Fixes: fa48d7e81624 ("usb: typec: ucsi: Do not call ACPI _DSM method for UCSI read operations")
> > Cc: stable <stable@xxxxxxxxxx>
>
> Oh, the stable tag has been mangled here.. I didn't notice this, sorry.
> Now Cc'ing the appropriate list.
It's not mangled at all, it's correct.
> Could you apply the patch to stables based on Fixes tag then, please?
> They are 6.12 and 6.13.
Will do so now, it was already in my queue.
thanks,
greg k-h
