On Sun, Mar 25, 2018 at 5:04 AM, Helge Deller <deller@xxxxxx> wrote: > Carlo Pisani noticed that his C3600 workstation behaved unstable during heavy > I/O on the PCI bus with a VIA VT6421 IDE/SATA PCI card. > > To avoid such instability, this patch switches the LBA PCI bus from Hard Fail > mode into Soft Fail mode. In this mode the bus will return -1UL for timed out > MMIO transactions, which is exactly how the x86 (and most other architectures) > PCI busses behave. > > This patch based on a proposal by Grant Grundler and Kyle McMartin 10 years ago: > https://www.spinics.net/lists/linux-parisc/msg01027.html > > Cc: Carlo Pisani <carlojpisani@xxxxxxxxx> > Cc: Kyle McMartin <kyle@xxxxxxxxxxx> > Cc: Grant Grundler <grantgrundler@xxxxxxxxx> > Signed-off-by: Helge Deller <deller@xxxxxx> LGTM. Reviewed-by: Grant Grundler <grantgrundler@xxxxxxxxx> cheers, grant > > diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c > index 41b740aed3a3..69bd98421eb1 100644 > --- a/drivers/parisc/lba_pci.c > +++ b/drivers/parisc/lba_pci.c > @@ -1403,9 +1403,27 @@ lba_hw_init(struct lba_device *d) > WRITE_REG32(stat, d->hba.base_addr + LBA_ERROR_CONFIG); > } > > - /* Set HF mode as the default (vs. -1 mode). */ > + > + /* > + * Hard Fail vs. Soft Fail on PCI "Master Abort". > + * > + * "Master Abort" means the MMIO transaction timed out - usually due to > + * the device not responding to an MMIO read. We would like HF to be > + * enabled to find driver problems, though it means the system will > + * crash with a HPMC. > + * > + * In SoftFail mode "~0L" is returned as a result of a timeout on the > + * pci bus. This is like how PCI busses on x86 and most other > + * architectures behave. In order to increase compatibility with > + * existing (x86) PCI hardware and existing Linux drivers we enable > + * Soft Faul mode on PA-RISC now too. > + */ > stat = READ_REG32(d->hba.base_addr + LBA_STAT_CTL); > +#if defined(ENABLE_HARDFAIL) > WRITE_REG32(stat | HF_ENABLE, d->hba.base_addr + LBA_STAT_CTL); > +#else > + WRITE_REG32(stat & ~HF_ENABLE, d->hba.base_addr + LBA_STAT_CTL); > +#endif > > /* > ** Writing a zero to STAT_CTL.rf (bit 0) will clear reset signal -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
