c7f57c6f92
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>
49 lines
1.4 KiB
C++
49 lines
1.4 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __UTILS_H__
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#define __UTILS_H__
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#include <stdint.h>
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#include <unistd.h>
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#include <utils/Timers.h>
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namespace android {
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class Timeout {
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public:
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Timeout() : mSystemEndTime(0) { }
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// Set a timeout which should occur msec milliseconds from now.
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// Negative values will cancel any current timeout;
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void setTimeout(int msec);
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// Return the number of milliseconds until the timeout occurs, or -1 if
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// no timeout is scheduled.
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int msecTillTimeout(nsecs_t nowTime);
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int msecTillTimeout() { return msecTillTimeout(systemTime()); }
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private:
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// The systemTime() at which the timeout will be complete, or 0 if no
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// timeout is currently scheduled.
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nsecs_t mSystemEndTime;
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};
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} // namespace android
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#endif // __UTILS_H__
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