Date: Tue, 13 Apr 1999 04:19:39 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: aa8vb@ipass.net (Randall Hopper) Cc: multimedia@FreeBSD.ORG Subject: Re: Bt848 corruption since upgrading to 3.1. Has DMA code changed? Message-ID: <199904130219.EAA07149@labinfo.iet.unipi.it> In-Reply-To: <19990412185441.A1581@ipass.net> from "Randall Hopper" at Apr 12, 99 06:54:22 pm
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I think i have an explaination on what happens... see below > Luigi Rizzo: > |> Also, the display freezes whenever I move a window over, but I'd assume > |> that's standard behaviour. > | > |this is because fxtv switches from direct video access to using X11 > |calls, and this causes a huge overload on the system (for moving > |video data). > > I don't think this explains no frames; maybe a good bit less, but he should > see a frame now and then or this is the result of something else. it depends, the user might exhaust its patience between "now" and "then"... > |in this respect fxtv should be a bit more adaptive -- when switching to > |use X11 it should really work one or two frames at a time and try to > |synchronize with the server. > > That's a thought. Though on my system here, I also can't get max frames > per second (NTSC = 30fps) on a zoomed TV window in XImages mode, and I > don't notice any loss in X server responsiveness with fxtv trying as hard > as it can. XFree seems to handle this load gracefully, blocking fxtv when > it's got enough images in the queue. not here... and is is on a K6-400 system with Matrox G200 video card on AGP bus. I can't try this at home (P133) because of the notorious problem i am having with the driver not reporting the 'full frame' interrupt because of what i suspect to be a dma overrun. i suspect in your case the whole thing might work with no reduction of responsiveness just for the above: the bt848 does not have enough memory bandwidth, the dma overruns and the driver does not report new frames until the XServer is done (more or less) and the bus is less loaded. On a fast system (and perhaps the video card on AGP) the bt848 has more bandwidth to proceed and bring the server to its knees. 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) -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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