On Wed, 24 Jun 2009, Jeff Garzik wrote: > Saeed Bishara wrote: > > The old value (0xbc) in cycles of the IORDY timeout is suitable for > > devices with core clock of 166 MHz, but some SoC controllers have > > faster core clocks. The new value will make the IORDY timeout large > > enough also for all SoC devices. > > > > Signed-off-by: Saeed Bishara <saeed@xxxxxxxxxxx> > > --- > > drivers/ata/sata_mv.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c > > index 23714ae..644436e 100644 > > --- a/drivers/ata/sata_mv.c > > +++ b/drivers/ata/sata_mv.c > > @@ -3368,7 +3368,7 @@ static void mv_soc_reset_hc_port(struct mv_host_priv *hpriv, > > ZERO(0x024); /* respq outp */ > > ZERO(0x020); /* respq inp */ > > ZERO(0x02c); /* test control */ > > - writel(0xbc, port_mmio + EDMA_IORDY_TMOUT); > > + writel(0x800, port_mmio + EDMA_IORDY_TMOUT); > > Do we really want to increase the timeout for older devices? How does > this change behavior for existing devices? This patch affects only soc devices, the 0xbc value sets the IORDY timeout to 1.25 micro seconds when the core clock is 150MHz (not 166MHz as I mentioned in the commit's message). This timeout defines the maximum time the cpu will be held when reading the PIO data register and no data is available. Sata devices usually fine with timeout, this means that during PIO data fises, the device will send the data dword within 1.25 micro seconds from the last one. Recent Marvell soc devices uses higher core clocks (e.g. 200MHz in kirkwood), so the IORDY timeout must be increased accordingly as it's defined in core clock cycle. I choose to use the value 0x800 so it will be good enough also for future devices, and, this large timeout will be good in case some sata device has big delays within its DATA fises. > > Jeff > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
