Duncan Sands wrote:
The potential issue with using unaligned buffers is related
to DMA-incoherent caches. If you have data laid out in memory
like this:
// cache line starts here
u8 cpu_writes_here_1 [size1];
u8 used_for_dma_read [dma_buflen];
u8 cpu_writes_here_2 [size2];
// c
> The potential issue with using unaligned buffers is related
> to DMA-incoherent caches. If you have data laid out in memory
> like this:
>
> // cache line starts here
> u8 cpu_writes_here_1 [size1];
> u8 used_for_dma_read [dma_buflen];
> u8 cpu_writes_here_2 [size2];
> /
Oliver Neukum wrote:
That means that you can't tell. So you must assume the worst.
The only safe usage with kmalloced memory is to have exactly
one buffer per kmalloced area and to start the buffer at offset 0.
None of the host controller hardware has alignment restrictions
for the start of DMA buf
Am Dienstag, 11. März 2003 16:43 schrieben Sie:
> On Monday 10 March 2003 7:36 pm, Oliver Neukum wrote:
> > Am Montag, 10. März 2003 13:59 schrieb Duncan Sands:
> > > Hi all, must the transfer_buffer I provide with an urb be
> > > aligned on, say, a double-word boundary or something like
> > > that
On Monday 10 March 2003 7:36 pm, Oliver Neukum wrote:
> Am Montag, 10. März 2003 13:59 schrieb Duncan Sands:
> > Hi all, must the transfer_buffer I provide with an urb be
> > aligned on, say, a double-word boundary or something like
> > that?
>
> The alignment requirements are specific to the hardw
On Mon, Mar 10, 2003 at 10:52:17AM -0800, Randy.Dunlap wrote:
> On Mon, 10 Mar 2003 19:36:04 +0100 Oliver Neukum <[EMAIL PROTECTED]> wrote:
>
> | Am Montag, 10. März 2003 13:59 schrieb Duncan Sands:
> | > Hi all, must the transfer_buffer I provide with an urb be
> | > aligned on, say, a double-wor
On Mon, 10 Mar 2003 19:36:04 +0100 Oliver Neukum <[EMAIL PROTECTED]> wrote:
| Am Montag, 10. März 2003 13:59 schrieb Duncan Sands:
| > Hi all, must the transfer_buffer I provide with an urb be
| > aligned on, say, a double-word boundary or something like
| > that?
|
| The alignment requirements a
Am Montag, 10. März 2003 13:59 schrieb Duncan Sands:
> Hi all, must the transfer_buffer I provide with an urb be
> aligned on, say, a double-word boundary or something like
> that?
The alignment requirements are specific to the hardware that happens
to be used. kmalloc() will return properly align
Hi all, must the transfer_buffer I provide with an urb be
aligned on, say, a double-word boundary or something like
that?
Thanks,
Duncan.
---
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_
