On Thu, Feb 10, 2011 at 4:07 PM, James Bottomley <James.Bottomley@xxxxxxx> wrote: > On Thu, 2011-02-10 at 10:18 +0100, Bartlomiej Zolnierkiewicz wrote: >> On Wed, Feb 9, 2011 at 7:00 PM, James Bottomley <James.Bottomley@xxxxxxx> wrote: >> > On Wed, 2011-02-09 at 15:15 +0100, Bartlomiej Zolnierkiewicz wrote: >> >> Add SCSI_QUIRKS config option (default y and dependent on EMBEDDED >> >> config option) to allow disabling of scsi_devinfo infrastructure. >> >> >> >> The output code size savings are ~14k for CONFIG_SCSI_QUIRKS=n >> >> (as measured on x86-32): >> > >> > I don't understand the point of this patch ... without the quirks SCSI >> > will do the wrong thing on a whole bunch of stuff. The savings look to >> > be tiny ... since the SCSI module is habitually a lot larger than your >> > figures suggest. >> >> The patch was originally done for embedded ATA-only setups. > > Well, if it's for ATA only then the better course would be extracting > libata from scsi. It's also a bit misleading to do sizings on x86, > because that doesn't imply embedded to me. Aren't there still ATAPI > devices that require the quirks? According to my knowledge all ATAPI quirks are handled locally in libata & sr. > Most embedded setups include some form of USB ... again, the pluggable > CD/DVD use the quirks table. This was done long time ago specifically for embedded 486-like embedded system w/o USB support and only using flash storage but indeed this is not a common case. > Given the potential for disaster even on embedded systems, I don't > really think something like this is a good idea. Well, I don't insist on applying it upstream as it is, it is more to show the direction where the possible room for improvements is in case of older/embedded systems and reducing memory/code size usage. [ There were some concerns about it during recent proposal to use more generalized code for support of some rare Intel-like PATA chipsets (which seem to cost ~20k as measured on x86-64 in terms of additional memory/code requirements, though most such systems are x86-32 only so the incurred cost is probably smaller) .] BTW with some effort we can do on-demand quirk table loading if it ever grows too big in the future. Thanks, Bartlomiej -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
