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In gcc4 structures are differently aligned compared to gcc3. Lots of 

structures can thus be misaligned for DMA when declared on stack.

The current atapi code accepts the misaligned dma's only screw's them up.
This small patch disables DMA for the rare transactions that are
misaligned. Note that all bulk-transfers are aligned due to page sizes.

See PR kern/34689
This commit is contained in:
reinoud 2006-10-01 20:10:31 +00:00
parent c443814068
commit c3af0f9a94
1 changed files with 7 additions and 3 deletions
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10
sys/dev/scsipi/atapi_wdc.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: atapi_wdc.c,v 1.102 2006/09/30 15:56:18 itohy Exp $ */
/* $NetBSD: atapi_wdc.c,v 1.103 2006/10/01 20:10:31 reinoud Exp $ */
/*
* Copyright (c) 1998, 2001 Manuel Bouyer.
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: atapi_wdc.c,v 1.102 2006/09/30 15:56:18 itohy Exp $");
__KERNEL_RCSID(0, "$NetBSD: atapi_wdc.c,v 1.103 2006/10/01 20:10:31 reinoud Exp $");
#ifndef ATADEBUG
#define ATADEBUG
@ -400,9 +400,13 @@ wdc_atapi_scsipi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
* 2 bytes. It's a bug to request such transfers for ATAPI
* but as the request can come from userland, we have to
* protect against it.
* Also some devices seems to not handle DMA xfers of less than
* Some devices can't cope with unaligned DMA xfers. These are
* normally only small structures since bulkdata is aligned.
* Also some devices seem to not handle DMA xfers of less than
* 4 bytes.
*/
if (((uintptr_t) sc_xfer->data) & 0x01)
xfer->c_flags &= ~C_DMA;
if (sc_xfer->datalen < 4 || (sc_xfer->datalen & 0x01))
xfer->c_flags &= ~C_DMA;
#endif /* NATA_DMA */