ubuntu-x-swat team mailing list archive

[Tormod Volden <670790@xxxxxxxxxxxxxxxxxx>]

After looking at it, I think the cast to float in the other code is
overkill, since the result also is an integer, and there is no
intermediate quotient, like in 3*(2/3) = 0. There are parentheses but
even without, multiplication and division goes from left to right so it
is like (3*2)/3 and nothing is lost. The only worry would be if the
intermediate product overflows, in which case a (single) cast to a
higher precision integer would make sense. In our case, dstBox->x1 etc
are screen coordinates so maximum in the order of 1000, and XExp1 etc
(from InitStreamsForExpansion) are up to 0xC. Since XExp1 etc are "int",
the multiplication is done with "int" (at least 32 bit) so it will not
overflow.

For preparing a proper patch there is not much to do, and I can walk you through it:
 git clone git://anongit.freedesktop.org/xorg/driver/xf86-video-savage # to retrieve the upstream tree
 (apply your patches)
 git commit -a -s  # and make a short comment
 git format-patch -o .. HEAD^
Send the resulting file to me for style review if you want. Make sure name and address in the patch header is how you would like to have it in the git history.

To start with I'd suggest you leave out the +7 removal. The rest is a
good and straight forward fix I would like to apply as soon as possible,
but the +7 removal is a separate issue which is more delicate.

Other improvements to the driver would be very cool! I agree this
hardware is perfectly usable for most tasks. Also the driver took many
years to get in good shape and it would a pity to let it rot. I have no
greater ambitions for its maintenance than to keep it falling into
pieces, but if there are still  interested users and developers like you
I will help with what I can. I am not familiar with all of the code, and
I never did much with xvideo or tv-out.

We should maybe take all this somewhere else, but just to comment quickly on your issues:
- TV resolutions are usually different than for monitors. I think PAL is 720x576.
- Scaling down should work fine with xvideo. Seems to work here.
- I believe the hardware is limited to 1024x1024 (source) for xvideo. So a movie of 1280x800 can not be scaled down with xvideo on savage.

Unfortunately I have no documentation. Just the savage guide linked from
here: http://dri.freedesktop.org/wiki/S3Savage

-- 
You received this bug notification because you are a member of Ubuntu-X,
which is subscribed to xserver-xorg-video-savage in Ubuntu.
https://bugs.launchpad.net/bugs/670790

Title:
  Xv / XVideo accelerated video width is limited by / depending on the
  screen resolution on S3 Savage, but only if the laptop LCD is the
  primary screen