Date: Sat, 16 Jan 1999 19:30:53 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: aa8vb@pagesz.net (Randall Hopper) Cc: duane@denton.com, multimedia@FreeBSD.ORG Subject: Re: fxtv Message-ID: <199901161830.TAA02503@labinfo.iet.unipi.it> In-Reply-To: <19990116123615.B11467@pagesz.net> from "Randall Hopper" at Jan 16, 99 12:35:56 pm
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> Same here :-)
>
> |1) ... When I click on the camera icon, the image stops (which I assume
> |is freeze). When I click on File->Save Image a dialog box pops up that
> |says "No frozen image to save." The same thing happens with Save Image
> |As. In other words, I cannot find a way to save an image.
Randall, i experienced similar problems for a long time on all
systems i have with a bt848. The reason is something i strongly
believe to be a bug in the bt848 driver:
when for any reason the DMA engine on the Bt848 experiences an
underrun, the interrupt handler in the bt848 driver notices the
problem and decides _not_ to invoke a wakeup() on the sleeping
process.
If you have this problem you should notice because with full screen
captures you don't have one field and the channel numbers and other
msgs remain partly visible (on the lines corresponding to the missing
field).
The reason i think this is broken behaviour of the driver is that the
interrupt handler should call wakeup() even in case of errors, just
report the problem to the application in case it bothers to check.
DMA overruns are easy, especially when (as in my case) one is dumping
to the video RAM of some slow card.
cheers
luigi
-----------------------------------+-------------------------------------
Luigi RIZZO .
EMAIL: luigi@iet.unipi.it . Dip. di Ing. dell'Informazione
HTTP://www.iet.unipi.it/~luigi/ . Universita` di Pisa
TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy)
-----------------------------------+-------------------------------------
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