Bartlomiej Zolnierkiewicz 60c3be387b ata_piix: parallel scanning on PATA needs an extra locking ... Commit log for commit 517d3cc15b ("[libata] ata_piix: Enable parallel scan") says: This patch turns on parallel scanning for the ata_piix driver. This driver is used on most netbooks (no AHCI for cheap storage it seems). The scan is the dominating time factor in the kernel boot for these devices; with this flag it gets cut in half for the device I used for testing (eeepc). Alan took a look at the driver source and concluded that it ought to be safe to do for this driver. Alan has also checked with the hardware team. and it is all true but once we put all things together additional constraints for PATA controllers show up (some hardware registers have per-host not per-port atomicity) and we risk misprogramming the controller. I used the following test to check whether the issue is real: @@ -736,8 +736,20 @@ static void piix_set_piomode(struct ata_ (timings[pio][1] << 8); } pci_write_config_word(dev, master_port, master_data); - if (is_slave) + if (is_slave) { + if (ap->port_no == 0) { + u8 tmp = slave_data; + + while (slave_data == tmp) { + pci_read_config_byte(dev, slave_port, &tmp); + msleep(50); + } + + dev_printk(KERN_ERR, &dev->dev, "PATA parallel scan " + "race detected\n"); + } pci_write_config_byte(dev, slave_port, slave_data); + } /* Ensure the UDMA bit is off - it will be turned back on if UDMA is selected */ and it indeed triggered the error message. Lets fix all such races by adding an extra locking to ->set_piomode and ->set_dmamode methods for PATA controllers. [ Alan: would be better to take the host lock in libata-core for these cases so that we fix all the adapters in one swoop. "Looks fine as a temproary quickfix tho" ] Cc: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Alan Cox <alan@linux.intel.com> Cc: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2009-08-31 17:25:00 -10:00
..
ahci.c	ahci: add workaround for on-board 5723s on some gigabyte boards	2009-08-12 06:21:32 -04:00
ata_generic.c
ata_piix.c	ata_piix: parallel scanning on PATA needs an extra locking	2009-08-31 17:25:00 -10:00
Kconfig	[libata] PATA driver for CF interface on AT91SAM9260 SoC	2009-06-23 01:54:24 -04:00
libata-acpi.c	trivial: fix typos s/paramter/parameter/ and s/excute/execute/ in documentation and source comments.	2009-06-12 18:01:46 +02:00
libata-core.c	libata: OCZ Vertex can't do HPA	2009-08-12 06:17:33 -04:00
libata-eh.c	libata: add missing NULL pointer check to ata_eh_reset()	2009-07-28 21:05:41 -04:00
libata-pmp.c
libata-scsi.c
libata-sff.c	libata-sff: avoid byte swapping in ata_sff_data_xfer()	2009-06-10 07:50:16 -04:00
libata.h
Makefile	[libata] PATA driver for CF interface on AT91SAM9260 SoC	2009-06-23 01:54:24 -04:00
pata_acpi.c
pata_ali.c	[libata] pata_ali: Use IGN_SIMPLEX	2009-06-05 17:10:54 -04:00
pata_amd.c
pata_artop.c
pata_at32.c
pata_at91.c	pata_at91: fix resource release	2009-08-12 06:16:47 -04:00
pata_atiixp.c	pata_atiixp: fix second channel support	2009-08-12 06:17:29 -04:00
pata_bf54x.c
pata_cmd64x.c
pata_cmd640.c
pata_cs5520.c
pata_cs5530.c
pata_cs5535.c
pata_cs5536.c
pata_cypress.c
pata_efar.c	pata_efar: fix PIO2 underclocking	2009-06-05 14:40:52 -04:00
pata_hpt3x2n.c
pata_hpt3x3.c
pata_hpt37x.c
pata_hpt366.c
pata_icside.c
pata_isapnp.c
pata_it821x.c
pata_it8213.c
pata_ixp4xx_cf.c
pata_jmicron.c
pata_legacy.c
pata_marvell.c
pata_mpc52xx.c	powerpc/5xxx: Add common mpc5xxx_get_bus_frequency() function	2009-06-17 00:30:22 -06:00
pata_mpiix.c
pata_netcell.c	pata_netcell: Fix typo	2009-06-08 09:12:28 -07:00
pata_ninja32.c
pata_ns87410.c
pata_ns87415.c
pata_octeon_cf.c	libata: remove superfluous NULL pointer checks	2009-07-28 21:06:13 -04:00
pata_of_platform.c
pata_oldpiix.c
pata_opti.c
pata_optidma.c
pata_palmld.c
pata_pcmcia.c	pata_pcmcia: add CNF-CDROM-ID	2009-07-28 21:05:18 -04:00
pata_pdc202xx_old.c
pata_pdc2027x.c
pata_platform.c
pata_qdi.c
pata_radisys.c
pata_rb532_cf.c
pata_rz1000.c
pata_sc1200.c
pata_scc.c
pata_sch.c
pata_serverworks.c
pata_sil680.c
pata_sis.c
pata_sl82c105.c
pata_triflex.c
pata_via.c
pata_winbond.c
pdc_adma.c
sata_fsl.c	sata_fsl: Add power mgmt support	2009-06-23 01:54:27 -04:00
sata_inic162x.c
sata_mv.c	libata: remove superfluous NULL pointer checks	2009-07-28 21:06:13 -04:00
sata_nv.c	sata_nv: MSI support, disabled by default	2009-08-12 06:20:29 -04:00
sata_promise.c
sata_promise.h
sata_qstor.c
sata_sil24.c
sata_sil.c	libata: remove superfluous NULL pointer checks	2009-07-28 21:06:13 -04:00
sata_sis.c
sata_svw.c
sata_sx4.c	sata_sx4: speed up ECC initialization	2009-06-10 07:50:17 -04:00
sata_uli.c
sata_via.c
sata_vsc.c
sis.h