[PATCH 3/6] pxa: fix pxa168 lcd controller vsync/hsync timing error
niej0001 at gmail.com
Tue Nov 10 00:18:42 EST 2009
2009/11/9 Eric Miao <eric.y.miao at gmail.com>:
>>> Could you please help double check this? My understanding is
>>> FB_SYNC_VERT_HIGH_ACT means it's a positive pulse covering all the
>>> valid HSYNCs, and a rising edge of VSYNC means a start of the frame.
>>> However, CFG_INV_VSYNC is '1' means the opposite.
>> My understanding is that high active means high level trigger new
>> frame/line. Below page support my point if it is not wrong.
> Tried to find the specific diagram in the spec on what CFG_INV_* means
> but failed, can you help verified this with an oscilloscope and let know
> the result? This is a fix then, and I'd like it to get into .32, sorry for late
If do not set CFG_INV_VSYNC and CFG_INV_HSYNC bits, controller output
is as below in oscilloscope.
|| || ||
.._________||_________||_________||____... HSYNC (active high)
.._____________________________| |_... VSYNC (active high)
So I should mark HSYNC_HIGH and VSYNC_HIGH in platform code and keep
driver code as below original code.
x |= (info->var.sync & FB_SYNC_VERT_HIGH_ACT) ? 0 : 0x00000008;
x |= (info->var.sync & FB_SYNC_HOR_HIGH_ACT) ? 0 : 0x00000004;
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