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SubjectRe: [PATCH 01/22] g_ncr5380: Remove CONFIG_SCSI_GENERIC_NCR53C400
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On 03/14/2016 05:27 AM, Finn Thain wrote:
> This change brings a number of improvements: fewer macros, better test
> coverage, simpler code and sane Kconfig options. The downside is a small
> chance of incompatibility (which seems unavoidable).
>
> CONFIG_SCSI_GENERIC_NCR53C400 exists to enable or inhibit pseudo DMA
> transfers when the driver is used with 53C400-compatible cards. Thanks to
> Ondrej Zary's patches, PDMA now works which means it can be enabled
> unconditionally.
>
> Due to bad design, CONFIG_SCSI_GENERIC_NCR53C400 ties together unrelated
> functionality as it sets both PSEUDO_DMA and BIOSPARAM macros. This patch
> effectively enables PSEUDO_DMA and disables BIOSPARAM.
>
> The defconfigs and the Kconfig default leave CONFIG_SCSI_GENERIC_NCR53C400
> undefined. Red Hat 9 and CentOS 2.1 were the same. This leaves both
> PSEUDO_DMA and BIOSPARAM disabled. The effect of this patch should be
> better performance from enabling PSEUDO_DMA.
>
> On the other hand, Debian 4 and SLES 10 had CONFIG_SCSI_GENERIC_NCR53C400
> enabled, so both PSEUDO_DMA and BIOSPARAM were enabled. This patch might
> affect configurations like this by disabling BIOSPARAM. My best guess is
> that this could be a problem only in the vanishingly rare case that
> 1) the CHS values stored in the boot device partition table are wrong and
> 2) a 5380 card is in use (because PDMA on 53C400 used to be broken).
>
> Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
>
> ---
>
Reviewed-by: Hannes Reinecke <hare@suse.com>

And don't worry about SLES10; we won't backport your fixes to _that_.

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

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