John Grossman c7f57c6f92 Fix for bug 6691452
Hand merge from ics-aah

> Fix for bug 6691452 : DO NOT MERGE
>
> As it so happens, there seem to be panels out there who disapprove of
> sudden changes in their HDMI clock rate.  In particular, Sony LCD
> panels made from around 2010-2011 (including the Sony GTV panel) seem
> to dislike this behavior.  When exposed to a large jump in the clock
> rate (say from -100pmm to +100ppm in about 30mSec), they seem to
> panic, blank their audio and video, and then resync.  The whole
> panic process takes about 2 seconds.
>
> The HDMI spec says that its clock jitter requirements are defined by
> their differential signalling eye diagram requirements relative to an
> "Ideal Recovery Clock" (see section 4.2.3.1 of the HDMI 1.3a spec).
> Basically, if you pass the eye diagram tests, you pass the clock
> jitter requirements.  We have determined in lab that even being
> extremely aggressive in our VCXO rate changes does not come even close
> to violating the HDMI eye diagrams.  Its just this era of Sony panels
> which seem to be upset by this behavior.
>
> One way or the other, experiments which the GTV devices have seemed to
> indicate that a full range sweep of the VCXO done in 10mSec steps over
> anything faster than 190mSec can cause trouble.  Adding a healthy
> degree of margin to this finding, the fix is to limit the rate of VCXO
> control change such that it never goes at a rate faster than
> FullRange/300mSec.
>
> Change flagged as do not merge due to the code structure changes to master.
> This will need to be merged by hand.
>
> Signed-off-by: John Grossman <johngro@google.com>
> Change-Id: Ibfd361fe1cc2cbd4909489e3317fb12e005c6a75

Change-Id: If62f791c826f1145262a6b546b1dc1f9776c37d8
Signed-off-by: John Grossman <johngro@google.com>
2012-06-29 10:22:19 -07:00

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1.2 KiB
C++

/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "utils.h"
namespace android {
void Timeout::setTimeout(int msec) {
if (msec < 0) {
mSystemEndTime = 0;
return;
}
mSystemEndTime = systemTime() + (static_cast<nsecs_t>(msec) * 1000000);
}
int Timeout::msecTillTimeout(nsecs_t nowTime) {
if (!mSystemEndTime) {
return -1;
}
if (mSystemEndTime < nowTime) {
return 0;
}
nsecs_t delta = mSystemEndTime - nowTime;
delta += 999999;
delta /= 1000000;
if (delta > 0x7FFFFFFF) {
return 0x7FFFFFFF;
}
return static_cast<int>(delta);
}
} // namespace android