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Date: Wed, 04 Dec 2013 00:17:56 +0100 From: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com> To: Leigh Brown <leigh@...inno.co.uk> CC: Russell King - ARM Linux <linux@....linux.org.uk>, Nicolas Schichan <nschichan@...ebox.fr>, Jason Cooper <jason@...edaemon.net>, netdev@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>, Florian Fainelli <florian@...nwrt.org>, "David S. Miller" <davem@...emloft.net>, linux-arm-kernel@...ts.infradead.org Subject: Re: Spurious timeouts in mvmdio On 12/04/2013 12:20 AM, Leigh Brown wrote: > On 2013-12-03 22:45, Sebastian Hesselbarth wrote: >> On 12/03/2013 09:57 PM, Leigh Brown wrote: > [...] >>> Nicolas' patch should fix the issue, but I prefer the following as it is >>> more >>> correct, as it only adjusts the timeout when calling >>> wait_event_timeout(). As >>> I said above,I believe the polling code is correct. >>> >>> diff --git a/drivers/net/ethernet/marvell/mvmdio.c >>> b/drivers/net/ethernet/marvell/mvmdio.c >>> index 7354960..b187c08 100644 >>> --- a/drivers/net/ethernet/marvell/mvmdio.c >>> +++ b/drivers/net/ethernet/marvell/mvmdio.c >>> @@ -92,6 +92,14 @@ static int orion_mdio_wait_ready(struct mii_bus *bus) >>> if (time_is_before_jiffies(end)) >>> ++timedout; >>> } else { >>> + /* >>> + * wait_event_timeout does not guarantee a delay of at >>> + * least one whole jiffie, so timeout must be no less >>> + * than two. >>> + */ >>> + if (timeout < 2) >>> + timeout = 2; >> >> If you always want to wait at least two jiffies, why not just increase >> TIMEOUT makro to 20ms instead of messing here with it again? >> As said on IRC log above, originally timeout was 100ms. > > You could do that, but would you not feel bad leaving a latent bug in > the code? > I know it's unlikely that someone would set HZ to 50, but if they did, > the same > bug would appear again. If you want to ensure timeout > 2, why not then just use: - unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT); + unsigned long timeout = 1 + usecs_to_jiffies(MVMDIO_SMI_TIMEOUT); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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