Re: [PATCH 3/6] pxa: fix pxa168 lcd controller vsync/hsync timing error

[Jun Nie <niej0001@gmail.com>]

2009/11/4 Eric Miao <eric.y.miao@gmail.com>:
> On Tue, Nov 3, 2009 at 2:45 PM, Jun Nie <niej0001@gmail.com> wrote:
>> pxa: fix pxa168 lcd controller vsync/hsync timing error
>>
>> Signed-off-by: Jun Nie <njun@marvell.com>
>> ---
>>  drivers/video/pxa168fb.c |    4 ++--
>>  include/video/pxa168fb.h |    2 --
>>  2 files changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/video/pxa168fb.c b/drivers/video/pxa168fb.c
>> index 2ba1444..bdd524c 100644
>> --- a/drivers/video/pxa168fb.c
>> +++ b/drivers/video/pxa168fb.c
>> @@ -459,8 +459,8 @@ static void set_dumb_panel_control(struct fb_info *info)
>>        x |= mi->invert_composite_blank ? 0x00000040 : 0;
>>        x |= (info->var.sync & FB_SYNC_COMP_HIGH_ACT) ? 0x00000020 : 0;
>>        x |= mi->invert_pix_val_ena ? 0x00000010 : 0;
>> -       x |= (info->var.sync & FB_SYNC_VERT_HIGH_ACT) ? 0 : 0x00000008;
>> -       x |= (info->var.sync & FB_SYNC_HOR_HIGH_ACT) ? 0 : 0x00000004;
>> +       x |= (info->var.sync & FB_SYNC_VERT_HIGH_ACT) ? 0x00000008 : 0;
>> +       x |= (info->var.sync & FB_SYNC_HOR_HIGH_ACT) ? 0x00000004 : 0;
>
> Hi Jun,
>
> 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.

http://www.arcadecollecting.com/info/Sync_fixing.txt

Jun