Messages in this thread | | | Subject | Re: [PATCH v3 3/9] media: adv7180: add support for NEWAVMODE | From | Steve Longerbeam <> | Date | Mon, 25 Jul 2016 15:04:02 -0700 |
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On 07/25/2016 12:36 PM, Ian Arkver wrote: > On 25/07/16 18:55, Steve Longerbeam wrote: >> On 07/25/2016 05:04 AM, Ian Arkver wrote: >>> On 23/07/16 18:00, Steve Longerbeam wrote: >>>> <snip> >>>> +#define ADV7180_VSYNC_FIELD_CTL_1_NEWAVMODE 0x02 >>> See below re this value. >>> >> Hi Ian, I double-checked the ADV7180 datasheet, this value is >> correct. Bit 4, when cleared, _enables_ NEWAVMODE. > > Hah, ok. I'm not familiar enough with the history of this chip and didn't > know what "OLDAVMODE" was. So, to enable NEWAVMODE you clear > the NEWAVMODE bit. That makes perfect sense. > > Anyway, I still don't see what NEWAVMODE gets you.
Hi Ian,
With video standard auto-detect disabled in the chip (VID_SEL > 2), captured NTSC images by the i.mx6q SabreAuto are corrupted, best I can describe it as "extremely fuzzy". Only when newavmode is enabled do the images look good again, in manual mode. With auto-detect enabled, images look good with or without newavmode.
The strange this is, the auto-detected standard is identical to the standard set explicitly in manual mode (NTSC-M). I did a complete i2c dump of the registers for both auto-detect and manual mode, and found no other differences besides the auto-detect/manual setting.
Trying to track this down further would probably require a logic analyzer on the bt.656 bus, which I don't have access to.
I will not be debugging this further so NEWAVMODE it will have to remain.
Steve
> As > far as I can see it just locks down the timings and removes the > flexibility > the chip otherwise offers to move the BT656 SAV and EAV codes around > relative to the incoming video. > > In what circumstances would you need to set the newavmode property > and change this default behaviour? We're not coupling the adv7180 > back-to-back with an ADV video encoder here, which is what > NEWAVMODE is for and is presumably why AD recommend it for their > eval boards. We're trying to get a BT656 compliant stream, which is > what the default mode purports to generate. > > Regards, > IanJ >
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