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List:       freedesktop-xorg
Subject:    Re: EXA pixmap alignments.
From:       Eric Anholt <eta () lclark ! edu>
Date:       2005-09-26 19:20:54
Message-ID: 1127762454.80757.13.camel () leguin
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On Mon, 2005-09-26 at 09:55 +0200, Thomas Hellstrom wrote:
> Hi!
> 
> EXADriverPtr->card.pixmapOffsetAlign = ?
> EXADriverPtr->card.pixmapPitchAlign = ?
> 
> Is there a chance to have the above parameters defined also for system 
> to frame-buffer transfers?
> 
> For example Unichrome / Unichrome Pro currently requires both to be 16 
> for PCI DMA to work, and as briefly discussed on the dri-devel list, 
> system / frame-buffer bounce buffers to fix alignments may be very 
> undesirable.

I'm not quite clear on what you're asking about -- you said something
about dst_addr%4 == src_addr%4.  EXA doesn't have anything to help you
with that -- it can only ensure that the offset in card space is aligned
to a multiple of some number, and/or the pitch of the pixmap is aligned
to some number.  However, simply having the on-card offset aligned to 16
and then doing a fixup on the system memory buffer (if necessary, which
it usually wouldn't be, I bet) after copying out seems reasonable to me.

-- 
Eric Anholt                                     eta@lclark.edu
http://people.freebsd.org/~anholt/              anholt@FreeBSD.org

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