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Commit 326e1c20 authored by Samuel Čavoj's avatar Samuel Čavoj Committed by Greg Kroah-Hartman
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usb: typec: ucsi: acpi: add quirk for ASUS Zenbook UM325

On some ACPI platforms (namely the ASUS Zenbook UM325) the _DSM method must
not be called after a notification is received but instead the mailbox
should be read immediately from RAM. This is because the ACPI interrupt
handler destroys the CCI in ERAM after copying to system memory, and when
_DSM is later called to perform a second copy, it retrieves a garbage
value.

Instead, the _DSM(read) method should only be called when necessary, i.e.
for polling the state after reset and for retrieving the version. Other
reads should not call _DSM and only peek into the RAM region.

This adds a separate read operation for the Zenbook that syncs the
ACPI mailbox only with polled commands.

Link: https://lore.kernel.org/linux-usb/20210823180626.tb6m7h5tp6adhvt2@fastboi.localdomain/


Signed-off-by: default avatarSamuel Čavoj <samuel@cavoj.net>
[ heikki : handling everything in ucsi_acpi.c with DMI quirk ]
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230405134456.49607-1-heikki.krogerus@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 917dc99b
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