From: Lv Zheng <lv.zheng@intel.com>
Date: Wed, 29 Oct 2014 03:33:43 +0000 (+0800)
Subject: Revert "ACPI / EC: Add support to disallow QR_EC to be issued before completing previ... 
X-Git-Tag: omap-for-v3.19/fixes-not-urgent-part1~20^2~1^3~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=df9ff91801da603079018f21a9412385b62f0f8e;p=pandora-kernel.git

Revert "ACPI / EC: Add support to disallow QR_EC to be issued before completing previous QR_EC"

It is reported that the following commit breaks Samsung hardware:
 Commit: 558e4736f2e1b0e6323adf7a5e4df77ed6cfc1a4.
 Subject: ACPI / EC: Add support to disallow QR_EC to be issued before
          completing previous QR_EC

Which means the Samsung behavior conflicts with the Acer behavior.

1. Samsung may behave like:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ] SCI_EVT set
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT clear
   Without the above commit, Samsung can work:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ] SCI_EVT set
                              write QR_EC
                              CAN prepare next QR_EC as SCI_EVT=1
                              read event
   [ -event 1 ] SCI_EVT clear
                              write QR_EC
                              read event
   [ -event 2 ] SCI_EVT clear
   With the above commit, Samsung cannot work:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ] SCI_EVT set
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT clear
                              CANNOT prepare next QR_EC as SCI_EVT=0
2. Acer may behave like:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ]
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT clear
   [ +event 2 ] SCI_EVT set
   Without the above commit, Acer cannot work when there is only 1 event:
   [ +event 1 ] SCI_EVT set
                              write QR_EC
                              can prepared next QR_EC as SCI_EVT=1
                              read event
   [ -event 1 ] SCI_EVT clear
                              CANNOT write QR_EC as SCI_EVT=0
   With the above commit, Acer can work:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ]
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT set
                              can prepare next QR_EC because SCI_EVT=0
                              CAN write QR_EC as SCI_EVT=1

Since Acer can also work with only the following commit applied:
 Commit: 3afcf2ece453e1a8c2c6de19cdf06da3772a1b08
 Subject: ACPI / EC: Add support to disallow QR_EC to be issued when
          SCI_EVT isn't set
commit 558e4736f2e1b0e6323adf7a5e4df77ed6cfc1a4 can be reverted.

Fixes: 558e4736f2e1 (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 Glück <odi@odi.ch>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: 3.17+ <stable@vger.kernel.org> # 3.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

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