PYXIS bug detection

From: Kurt Garloff (
Date: Tue Dec 11 2001 - 10:22:18 EST

Hi Ivan, Jay,

so far I failed to come up with a routine for the pyxis DMA read page
boundary cross corruption.

The attached patch has two routines to try, but both fail:

check_pyxis_pagecross_bug2 does not find any corruption.
check_pyxis_pagecross_bug apparently does not read from the memory region I
  intended and will thus always report corruption.

What am I doing wrong? (I'm still new to Alpha, so my understanding of PTEs
and the MMU setup on alpha is limited.)

For now, I always set the have_pyxis_pagecross_bug when a pyxis is detected.

One more patch attached: The ide-dma changes that make actually use of this
flag and work around the chipset bug by not creating sg segments that cross
page boundaries on writes (i.e. DME mem reads).


Kurt Garloff                   <>         [Eindhoven, NL]
Physics: Plasma simulations  <K.Garloff@Phys.TUE.NL>  [TU Eindhoven, NL]
Linux: SCSI, Security          <>    [SuSE Nuernberg, DE]
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This archive was generated by hypermail 2b29 : Sat Dec 15 2001 - 21:00:33 EST