ACPI / EC: Fix regression due to conflicting firmware behavior between Samsung and...
authorLv Zheng <lv.zheng@intel.com>
Wed, 29 Oct 2014 03:33:49 +0000 (11:33 +0800)
committerBen Hutchings <ben@decadent.org.uk>
Fri, 20 Feb 2015 00:49:40 +0000 (00:49 +0000)
commitbb5850b1a1c3ffd6b6f28262b934165a76cb911a
tree4cd69d06479dc2c9bbde1749601783e68b9773cb
parent309adf3c8062595aeea4f388f2ff7f9492e50979
ACPI / EC: Fix regression due to conflicting firmware behavior between Samsung and Acer.

commit 79149001105f18bd2285ada109f9229ea24a7571 upstream.

It is reported that Samsung laptops that need to poll events are broken by
the following commit:
 Commit 3afcf2ece453e1a8c2c6de19cdf06da3772a1b08
 Subject: ACPI / EC: Add support to disallow QR_EC to be issued when SCI_EVT isn't set

The behaviors of the 2 vendor firmwares are conflict:
 1. Acer: OSPM shouldn't issue QR_EC unless SCI_EVT is set, firmware
         automatically sets SCI_EVT as long as there is event queued up.
 2. Samsung: OSPM should issue QR_EC whatever SCI_EVT is set, firmware
            returns 0 when there is no event queued up.

This patch is a quick fix to distinguish the behaviors to make Acer
behavior only effective for Acer EC firmware so that the breakages on
Samsung EC firmware can be avoided.

Fixes: 3afcf2ece453 (ACPI / EC: Add support to disallow QR_EC to be issued ...)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=44161
Reported-and-tested-by: Ortwin Gl├╝ck <odi@odi.ch>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[ rjw : Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Kamal Mostafa <kamal@canonical.com>
drivers/acpi/ec.c