On occasion, a user will submit a patch that enables the "mod15write"
quirk for their device. Enabling this quirk has the effect of clamping
all ATA commands to no more than 15 sectors. The intended use of this
quirk is to stop the controller from generating FIS's of unusual size
("but Wesley, what about the FOUS's?"), which in turn works around
problems in a <list> of hard drives.
One side effect of this quirk is greatly decreased performance. Users
often enable the mod15write quirk to fix various system, power, chip,
and/or driver problems. For a few rare problematic cases, enabling this
has cured lockups or data corruption.
Rather than add bogus listings to the mod15write quirk list (I get a
patch every month doing such), we add a 'slow_down' module parameter.
This allows users to employ a performance sledgehammer in the hopes
of curing a problem. It defaults to off (0), of course.
Reflect changes in SCSI midlayer and updated to use new
ordered request implementation
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Hi,
the patch below marks several libata (and libata-driver) structures
const so that they end up in the .rodata segment and don't false-share
cachelines with things that get dirtied often.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
- changes license of all code from OSL+GPL to plain ole GPL
- except for NVIDIA, who hasn't yet responded about sata_nv
- copyright holders were already contacted privately
- adds info in each driver about where hardware/protocol docs may be
obtained
- where I have made major contributions, updated copyright dates
As SII reports that only original 3112's are affected by M15W quirk,
This patch adds SIL_FLAG_MOD15WRITE to selectively apply M15W quirk
depending on chipsets. As of yet, we don't know exactly which PCI IDs
are for original 3112, so M15W quirk is applied to all except for 3512
and 3124. Once more info is avaliable, we can change some of these
sil_3112_m15w's to sil_3112.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Jens Axboe pointed out that the iounmap() call in libata was occurring
too early, and some drivers (ahci, probably others) were using ioremap'd
memory after it had been unmapped.
The patch should address that problem by way of improving the libata
driver API:
* move ->host_stop() call after all ->port_stop() calls have occurred.
* create default helper function ata_host_stop(), and move iounmap()
call there.
* add ->host_stop_prewalk() hook, use it in sata_qstor.c (hi Mark).
sata_qstor appears to require the host-stop-before-port-stop ordering
that existed prior to applying the attached patch.
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
