| Message ID | 20081031155421.GB6181@gospo.rdu.redhat.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
Andy Gospodarek wrote: > Systems that use MSI do not report the correct 'Interrupt' value in > ifconfig output. This patch sets dev->irq after initializing the > interrupt as the value will change when using MSI. > > I suspect this is a problem with a lot of drivers, so I'll snoop around > and post some more patches if needed. > > Signed-off-by: Andy Gospodarek <andy@greyhouse.net> > --- > > tg3.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c > index eb9f8f3..fa95e99 100644 > --- a/drivers/net/tg3.c > +++ b/drivers/net/tg3.c > @@ -7892,6 +7892,7 @@ static int tg3_request_irq(struct tg3 *tp) > irq_handler_t fn; > unsigned long flags; > struct net_device *dev = tp->dev; > + int ret; > > if (tp->tg3_flags2 & TG3_FLG2_USING_MSI) { > fn = tg3_msi; > @@ -7904,7 +7905,9 @@ static int tg3_request_irq(struct tg3 *tp) > fn = tg3_interrupt_tagged; > flags = IRQF_SHARED | IRQF_SAMPLE_RANDOM; > } > - return (request_irq(tp->pdev->irq, fn, flags, dev->name, dev)); > + ret = request_irq(tp->pdev->irq, fn, flags, dev->name, dev); > + dev->irq = tp->pdev->irq; > + return ret; The ifconfig value is useless, and was never designed to carry and display that kind of information (MSI vectors, etc.). In fact, part of the reason why the ethtool bus-id information was added was to give better insight into the hardware attached to the device, notably including the interrupt information. In modern drivers (read: newer than [E]ISA), dev->irq use is inconsistent and largely for __best effort__ display purposes only. I'd argue that a policy of leaving dev->irq at zero might be a better idea. That ensures users do not pay attention to what is already an inconsistent/truncate/device-dependent piece of information. Jeff -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Oct 31, 2008 at 12:09:08PM -0400, Jeff Garzik wrote: > Andy Gospodarek wrote: >> Systems that use MSI do not report the correct 'Interrupt' value in >> ifconfig output. This patch sets dev->irq after initializing the >> interrupt as the value will change when using MSI. >> >> I suspect this is a problem with a lot of drivers, so I'll snoop around >> and post some more patches if needed. >> >> Signed-off-by: Andy Gospodarek <andy@greyhouse.net> >> --- >> >> tg3.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c >> index eb9f8f3..fa95e99 100644 >> --- a/drivers/net/tg3.c >> +++ b/drivers/net/tg3.c >> @@ -7892,6 +7892,7 @@ static int tg3_request_irq(struct tg3 *tp) >> irq_handler_t fn; >> unsigned long flags; >> struct net_device *dev = tp->dev; >> + int ret; >> if (tp->tg3_flags2 & TG3_FLG2_USING_MSI) { >> fn = tg3_msi; >> @@ -7904,7 +7905,9 @@ static int tg3_request_irq(struct tg3 *tp) >> fn = tg3_interrupt_tagged; >> flags = IRQF_SHARED | IRQF_SAMPLE_RANDOM; >> } >> - return (request_irq(tp->pdev->irq, fn, flags, dev->name, dev)); >> + ret = request_irq(tp->pdev->irq, fn, flags, dev->name, dev); >> + dev->irq = tp->pdev->irq; >> + return ret; > > The ifconfig value is useless, and was never designed to carry and > display that kind of information (MSI vectors, etc.). > > In fact, part of the reason why the ethtool bus-id information was added > was to give better insight into the hardware attached to the device, > notably including the interrupt information. > > In modern drivers (read: newer than [E]ISA), dev->irq use is > inconsistent and largely for __best effort__ display purposes only. > > I'd argue that a policy of leaving dev->irq at zero might be a better > idea. That ensures users do not pay attention to what is already an > inconsistent/truncate/device-dependent piece of information. > This came up because the output is currently wrong. # ifconfig eth0 | grep Inter && grep eth0 /proc/interrupts Interrupt:169 Memory:f6000000-f6012100 122: 2894 0 0 PCI-MSI eth0 Some drivers take the stand of not setting dev->irq anything (like most of the Intel drivers), but I didn't take that route with tg3 (or with the others I'd planned) simply because I didn't want to hear crying about breaking user-space with a patch that would make that line disappear. If this seems like a reasonable change that we can force on user-space I'll post a patch that drops the setting of dev->irq all together, so this disappers. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Andy Gospodarek wrote: > On Fri, Oct 31, 2008 at 12:09:08PM -0400, Jeff Garzik wrote: >> Andy Gospodarek wrote: >>> Systems that use MSI do not report the correct 'Interrupt' value in >>> ifconfig output. This patch sets dev->irq after initializing the >>> interrupt as the value will change when using MSI. >>> >>> I suspect this is a problem with a lot of drivers, so I'll snoop around >>> and post some more patches if needed. >>> >>> Signed-off-by: Andy Gospodarek <andy@greyhouse.net> >>> --- >>> >>> tg3.c | 5 ++++- >>> 1 file changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c >>> index eb9f8f3..fa95e99 100644 >>> --- a/drivers/net/tg3.c >>> +++ b/drivers/net/tg3.c >>> @@ -7892,6 +7892,7 @@ static int tg3_request_irq(struct tg3 *tp) >>> irq_handler_t fn; >>> unsigned long flags; >>> struct net_device *dev = tp->dev; >>> + int ret; >>> if (tp->tg3_flags2 & TG3_FLG2_USING_MSI) { >>> fn = tg3_msi; >>> @@ -7904,7 +7905,9 @@ static int tg3_request_irq(struct tg3 *tp) >>> fn = tg3_interrupt_tagged; >>> flags = IRQF_SHARED | IRQF_SAMPLE_RANDOM; >>> } >>> - return (request_irq(tp->pdev->irq, fn, flags, dev->name, dev)); >>> + ret = request_irq(tp->pdev->irq, fn, flags, dev->name, dev); >>> + dev->irq = tp->pdev->irq; >>> + return ret; >> The ifconfig value is useless, and was never designed to carry and >> display that kind of information (MSI vectors, etc.). >> >> In fact, part of the reason why the ethtool bus-id information was added >> was to give better insight into the hardware attached to the device, >> notably including the interrupt information. >> >> In modern drivers (read: newer than [E]ISA), dev->irq use is >> inconsistent and largely for __best effort__ display purposes only. >> >> I'd argue that a policy of leaving dev->irq at zero might be a better >> idea. That ensures users do not pay attention to what is already an >> inconsistent/truncate/device-dependent piece of information. >> > > This came up because the output is currently wrong. > > # ifconfig eth0 | grep Inter && grep eth0 /proc/interrupts > Interrupt:169 Memory:f6000000-f6012100 > 122: 2894 0 0 PCI-MSI eth0 > > Some drivers take the stand of not setting dev->irq anything (like most > of the Intel drivers), but I didn't take that route with tg3 (or with > the others I'd planned) simply because I didn't want to hear crying > about breaking user-space with a patch that would make that line > disappear. > > If this seems like a reasonable change that we can force on user-space > I'll post a patch that drops the setting of dev->irq all together, so > this disappers. I would vote for zeroing dev->irq in not only tg3, but also other modern, ethtool-enabled drivers... It is a relic of the ISA days, and is incompatible with multiple MSI vector scenarios, something also found on some non-x86 and embedded ethernet drivers. For years now, dev->irq has been providing information on an unreliable, best-effort basis. I prefer definitive, reliable, predictable behaviors, and think always-zero is therefore an improvement. Comments welcome... Jeff -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Jeff Garzik <jeff@garzik.org> Date: Fri, 31 Oct 2008 12:47:50 -0400 > Andy Gospodarek wrote: > > This came up because the output is currently wrong. > > # ifconfig eth0 | grep Inter && grep eth0 /proc/interrupts > > Interrupt:169 Memory:f6000000-f6012100 > > 122: 2894 0 0 PCI-MSI eth0 > > Some drivers take the stand of not setting dev->irq anything (like most > > of the Intel drivers), but I didn't take that route with tg3 (or with > > the others I'd planned) simply because I didn't want to hear crying > > about breaking user-space with a patch that would make that line > > disappear. > > If this seems like a reasonable change that we can force on user-space > > I'll post a patch that drops the setting of dev->irq all together, so > > this disappers. > > I would vote for zeroing dev->irq in not only tg3, but also other > modern, ethtool-enabled drivers... It is a relic of the ISA days, > and is incompatible with multiple MSI vector scenarios, something > also found on some non-x86 and embedded ethernet drivers. > > For years now, dev->irq has been providing information on an > unreliable, best-effort basis. I prefer definitive, reliable, > predictable behaviors, and think always-zero is therefore an > improvement. > > Comments welcome... I completely agree with Jeff and I'll happily take patches which do this into net-next-2.6 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c index eb9f8f3..fa95e99 100644 --- a/drivers/net/tg3.c +++ b/drivers/net/tg3.c @@ -7892,6 +7892,7 @@ static int tg3_request_irq(struct tg3 *tp) irq_handler_t fn; unsigned long flags; struct net_device *dev = tp->dev; + int ret; if (tp->tg3_flags2 & TG3_FLG2_USING_MSI) { fn = tg3_msi; @@ -7904,7 +7905,9 @@ static int tg3_request_irq(struct tg3 *tp) fn = tg3_interrupt_tagged; flags = IRQF_SHARED | IRQF_SAMPLE_RANDOM; } - return (request_irq(tp->pdev->irq, fn, flags, dev->name, dev)); + ret = request_irq(tp->pdev->irq, fn, flags, dev->name, dev); + dev->irq = tp->pdev->irq; + return ret; } static int tg3_test_interrupt(struct tg3 *tp)
Systems that use MSI do not report the correct 'Interrupt' value in ifconfig output. This patch sets dev->irq after initializing the interrupt as the value will change when using MSI. I suspect this is a problem with a lot of drivers, so I'll snoop around and post some more patches if needed. Signed-off-by: Andy Gospodarek <andy@greyhouse.net> --- tg3.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html