From: Joe Korty Fix occasional PCI bus parity errors on the Dell PowerEdge 4600 during boot. Symptoms: The LCD display would turn orange and display "PCI SYSTEM E13F5", and the following message would appear in /var/log/dmesg: "Uhhuh. NMI received. Dazed and confused, but trying to continue". By inserting a PCI card with a PDC20268 IDE controller and attaching to that a Sony DRU-510A DVD RW burner with an unloaded tray, the failure can be made to happen on every boot. Cause: The aic7xxx driver was resetting the onboard AIC7891 SCSI controller while waiting for a previous reset to complete. This second reset confuses the controller causing it to put bad data onto the PCI bus. This is a backport of a RedHat 2.4.21-15.ELsmp fix. A letter discussing this problem, or one very close to it, may be found at: http://lists.us.dell.com/pipermail/linux-poweredge/2003-May/025010.html Signed-off-by: Andrew Morton --- 25-akpm/drivers/scsi/aic7xxx/aic79xx_pci.c | 4 +++- 25-akpm/drivers/scsi/aic7xxx/aic7xxx_pci.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff -puN drivers/scsi/aic7xxx/aic79xx_pci.c~fix-double-reset-in-aic7xxx-driver drivers/scsi/aic7xxx/aic79xx_pci.c --- 25/drivers/scsi/aic7xxx/aic79xx_pci.c~fix-double-reset-in-aic7xxx-driver 2004-07-26 14:54:35.115967248 -0700 +++ 25-akpm/drivers/scsi/aic7xxx/aic79xx_pci.c 2004-07-26 14:54:35.121966336 -0700 @@ -452,8 +452,10 @@ ahd_pci_test_register_access(struct ahd_ * or read prefetching could be initiated by the * CPU or host bridge. Our device does not support * either, so look for data corruption and/or flaged - * PCI errors. + * PCI errors. First pause without causing another + * chip reset. */ + hcntrl &= ~CHIPRST; ahd_outb(ahd, HCNTRL, hcntrl|PAUSE); while (ahd_is_paused(ahd) == 0) ; diff -puN drivers/scsi/aic7xxx/aic7xxx_pci.c~fix-double-reset-in-aic7xxx-driver drivers/scsi/aic7xxx/aic7xxx_pci.c --- 25/drivers/scsi/aic7xxx/aic7xxx_pci.c~fix-double-reset-in-aic7xxx-driver 2004-07-26 14:54:35.117966944 -0700 +++ 25-akpm/drivers/scsi/aic7xxx/aic7xxx_pci.c 2004-07-26 14:54:35.123966032 -0700 @@ -1284,8 +1284,10 @@ ahc_pci_test_register_access(struct ahc_ * or read prefetching could be initiated by the * CPU or host bridge. Our device does not support * either, so look for data corruption and/or flagged - * PCI errors. + * PCI errors. First pause without causing another + * chip reset. */ + hcntrl &= ~CHIPRST; ahc_outb(ahc, HCNTRL, hcntrl|PAUSE); while (ahc_is_paused(ahc) == 0) ; _