| Message ID | 1448902811-11399-2-git-send-email-l.stach@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Nov 30, 2015 at 06:00:11PM +0100, Lucas Stach wrote: > This has been stable on i.MX6 for a good while now and there is no > reason to keep it disabled, as it allows to allocate non-shared > IRQs if several PCIe devices are connected to a single host. > > Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Applied, thanks.
On Mon, Nov 30, 2015 at 9:00 AM, Lucas Stach <l.stach@pengutronix.de> wrote: > This has been stable on i.MX6 for a good while now and there is no > reason to keep it disabled, as it allows to allocate non-shared > IRQs if several PCIe devices are connected to a single host. > > Signed-off-by: Lucas Stach <l.stach@pengutronix.de> > --- > arch/arm/configs/imx_v6_v7_defconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig > index 4187f69f6630..e2ce60d00e8a 100644 > --- a/arch/arm/configs/imx_v6_v7_defconfig > +++ b/arch/arm/configs/imx_v6_v7_defconfig > @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y > CONFIG_SOC_LS1021A=y > CONFIG_SOC_VF610=y > CONFIG_PCI=y > +CONFIG_PCI_MSI=y > CONFIG_PCI_IMX6=y > CONFIG_SMP=y > CONFIG_PREEMPT_VOLUNTARY=y > -- > 2.6.2 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel Lucas, Any thoughts on why enabling MSI on IMX6 breaks legacy interrupts? Again, many PCI devices/drivers don't support MSI and thus enabling MSI as this patch does makes this config break many PCI devices on IMX6. I have found that MSI does indeed work on the IMX6 for cards/drivers that use MSI, but for those that don't the legacy interrupts never fire regardless of going through a bridge or directly hanging off the IMX6. I assume you can confirm this on your boards/devices as well? Regards, Tim
Am Donnerstag, den 14.04.2016, 08:13 -0700 schrieb Tim Harvey: > On Mon, Nov 30, 2015 at 9:00 AM, Lucas Stach <l.stach@pengutronix.de> wrote: > > This has been stable on i.MX6 for a good while now and there is no > > reason to keep it disabled, as it allows to allocate non-shared > > IRQs if several PCIe devices are connected to a single host. > > > > Signed-off-by: Lucas Stach <l.stach@pengutronix.de> > > --- > > arch/arm/configs/imx_v6_v7_defconfig | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig > > index 4187f69f6630..e2ce60d00e8a 100644 > > --- a/arch/arm/configs/imx_v6_v7_defconfig > > +++ b/arch/arm/configs/imx_v6_v7_defconfig > > @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y > > CONFIG_SOC_LS1021A=y > > CONFIG_SOC_VF610=y > > CONFIG_PCI=y > > +CONFIG_PCI_MSI=y > > CONFIG_PCI_IMX6=y > > CONFIG_SMP=y > > CONFIG_PREEMPT_VOLUNTARY=y > > -- > > 2.6.2 > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > Lucas, > > Any thoughts on why enabling MSI on IMX6 breaks legacy interrupts? > > Again, many PCI devices/drivers don't support MSI and thus enabling > MSI as this patch does makes this config break many PCI devices on > IMX6. > > I have found that MSI does indeed work on the IMX6 for cards/drivers > that use MSI, but for those that don't the legacy interrupts never > fire regardless of going through a bridge or directly hanging off the > IMX6. I assume you can confirm this on your boards/devices as well? > No, this seems to be an errata in the DW PCIe core. The manual states that legacy IRQs and MSIs can't be used together, but I thought this only applies to the EP part of the core. We can probably fix the simple configuration by not enabling MSI support until someone actually requests to set up an MSI IRQ, so both IRQ types work when only one EP is connected. I don't have any idea yet how to fix setups with a PCIe switch where some connected EPs might like to use MSIs while some others can't use them. Regards, Lucas
On Fri, Apr 15, 2016 at 1:21 AM, Lucas Stach <l.stach@pengutronix.de> wrote: > Am Donnerstag, den 14.04.2016, 08:13 -0700 schrieb Tim Harvey: >> On Mon, Nov 30, 2015 at 9:00 AM, Lucas Stach <l.stach@pengutronix.de> wrote: >> > This has been stable on i.MX6 for a good while now and there is no >> > reason to keep it disabled, as it allows to allocate non-shared >> > IRQs if several PCIe devices are connected to a single host. >> > >> > Signed-off-by: Lucas Stach <l.stach@pengutronix.de> >> > --- >> > arch/arm/configs/imx_v6_v7_defconfig | 1 + >> > 1 file changed, 1 insertion(+) >> > >> > diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig >> > index 4187f69f6630..e2ce60d00e8a 100644 >> > --- a/arch/arm/configs/imx_v6_v7_defconfig >> > +++ b/arch/arm/configs/imx_v6_v7_defconfig >> > @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y >> > CONFIG_SOC_LS1021A=y >> > CONFIG_SOC_VF610=y >> > CONFIG_PCI=y >> > +CONFIG_PCI_MSI=y >> > CONFIG_PCI_IMX6=y >> > CONFIG_SMP=y >> > CONFIG_PREEMPT_VOLUNTARY=y >> > -- >> > 2.6.2 >> > >> > >> > _______________________________________________ >> > linux-arm-kernel mailing list >> > linux-arm-kernel@lists.infradead.org >> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >> >> Lucas, >> >> Any thoughts on why enabling MSI on IMX6 breaks legacy interrupts? >> >> Again, many PCI devices/drivers don't support MSI and thus enabling >> MSI as this patch does makes this config break many PCI devices on >> IMX6. >> >> I have found that MSI does indeed work on the IMX6 for cards/drivers >> that use MSI, but for those that don't the legacy interrupts never >> fire regardless of going through a bridge or directly hanging off the >> IMX6. I assume you can confirm this on your boards/devices as well? >> > No, this seems to be an errata in the DW PCIe core. The manual states > that legacy IRQs and MSIs can't be used together, but I thought this > only applies to the EP part of the core. > > We can probably fix the simple configuration by not enabling MSI support > until someone actually requests to set up an MSI IRQ, so both IRQ types > work when only one EP is connected. > I don't have any idea yet how to fix setups with a PCIe switch where > some connected EPs might like to use MSIs while some others can't use > them. > > Regards, > Lucas > Lucas, I feel a bit dumb here for forgetting about this issue and letting it drop, but I've just spent a day debugging an issue with the ath9k wireless driver only to realize it was that the ath9k card and/or driver doesn't support MSI interrupts and thus no longer work on mainline kernels that have MSI enabled. To be honest I'm not sure how many PCIe devices out there can't support MSI because of hardware limitations vs drivers that simply have not implemented it. To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes it such that you can't disable MSI on the IMX6. Is there some fix you can think of to make the IMX6 PCIe host controller raise an interrupt for cards/drivers that use legacy irq's? If not, then we need to allow MSI to be disabled for IMX6 and default it to disabled for compatibility. Regards, Tim
On Thu, Mar 30, 2017 at 4:42 PM, Tim Harvey <tharvey@gateworks.com> wrote: > On Fri, Apr 15, 2016 at 1:21 AM, Lucas Stach <l.stach@pengutronix.de> wrote: >> Am Donnerstag, den 14.04.2016, 08:13 -0700 schrieb Tim Harvey: >>> On Mon, Nov 30, 2015 at 9:00 AM, Lucas Stach <l.stach@pengutronix.de> wrote: >>> > This has been stable on i.MX6 for a good while now and there is no >>> > reason to keep it disabled, as it allows to allocate non-shared >>> > IRQs if several PCIe devices are connected to a single host. >>> > >>> > Signed-off-by: Lucas Stach <l.stach@pengutronix.de> >>> > --- >>> > arch/arm/configs/imx_v6_v7_defconfig | 1 + >>> > 1 file changed, 1 insertion(+) >>> > >>> > diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig >>> > index 4187f69f6630..e2ce60d00e8a 100644 >>> > --- a/arch/arm/configs/imx_v6_v7_defconfig >>> > +++ b/arch/arm/configs/imx_v6_v7_defconfig >>> > @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y >>> > CONFIG_SOC_LS1021A=y >>> > CONFIG_SOC_VF610=y >>> > CONFIG_PCI=y >>> > +CONFIG_PCI_MSI=y >>> > CONFIG_PCI_IMX6=y >>> > CONFIG_SMP=y >>> > CONFIG_PREEMPT_VOLUNTARY=y >>> > -- >>> > 2.6.2 >>> > >>> > >>> > _______________________________________________ >>> > linux-arm-kernel mailing list >>> > linux-arm-kernel@lists.infradead.org >>> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>> >>> Lucas, >>> >>> Any thoughts on why enabling MSI on IMX6 breaks legacy interrupts? >>> >>> Again, many PCI devices/drivers don't support MSI and thus enabling >>> MSI as this patch does makes this config break many PCI devices on >>> IMX6. >>> >>> I have found that MSI does indeed work on the IMX6 for cards/drivers >>> that use MSI, but for those that don't the legacy interrupts never >>> fire regardless of going through a bridge or directly hanging off the >>> IMX6. I assume you can confirm this on your boards/devices as well? >>> >> No, this seems to be an errata in the DW PCIe core. The manual states >> that legacy IRQs and MSIs can't be used together, but I thought this >> only applies to the EP part of the core. >> >> We can probably fix the simple configuration by not enabling MSI support >> until someone actually requests to set up an MSI IRQ, so both IRQ types >> work when only one EP is connected. >> I don't have any idea yet how to fix setups with a PCIe switch where >> some connected EPs might like to use MSIs while some others can't use >> them. >> >> Regards, >> Lucas >> > > Lucas, > > I feel a bit dumb here for forgetting about this issue and letting it > drop, but I've just spent a day debugging an issue with the ath9k > wireless driver only to realize it was that the ath9k card and/or > driver doesn't support MSI interrupts and thus no longer work on > mainline kernels that have MSI enabled. To be honest I'm not sure how > many PCIe devices out there can't support MSI because of hardware > limitations vs drivers that simply have not implemented it. > > To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes > it such that you can't disable MSI on the IMX6. > > Is there some fix you can think of to make the IMX6 PCIe host > controller raise an interrupt for cards/drivers that use legacy irq's? > If not, then we need to allow MSI to be disabled for IMX6 and default > it to disabled for compatibility. > Joao / Jingoo, (Adding linux-pci to the list to pick up maintainers of other DWC PCIe core drivers) Is Luca's statement that 'legacy IRQs and MSIs can't be used together' true in general for the DW PCIe core? If any of the host controllers using this core can't support both legacy and MSI irqs together I still believe we shouldn't enable/require MSI as it breaks any card/driver that only supports legacy interrupts (such as ath9k). Regards, Tim
On Friday, March 31, 2017 12:05 PM, Tim Harvey wrote: > On Thu, Mar 30, 2017 at 4:42 PM, Tim Harvey <tharvey@gateworks.com> wrote: > > On Fri, Apr 15, 2016 at 1:21 AM, Lucas Stach <l.stach@pengutronix.de> > wrote: > >> Am Donnerstag, den 14.04.2016, 08:13 -0700 schrieb Tim Harvey: > >>> On Mon, Nov 30, 2015 at 9:00 AM, Lucas Stach <l.stach@pengutronix.de> > wrote: > >>> > This has been stable on i.MX6 for a good while now and there is no > >>> > reason to keep it disabled, as it allows to allocate non-shared > >>> > IRQs if several PCIe devices are connected to a single host. > >>> > > >>> > Signed-off-by: Lucas Stach <l.stach@pengutronix.de> > >>> > --- > >>> > arch/arm/configs/imx_v6_v7_defconfig | 1 + > >>> > 1 file changed, 1 insertion(+) > >>> > > >>> > diff --git a/arch/arm/configs/imx_v6_v7_defconfig > b/arch/arm/configs/imx_v6_v7_defconfig > >>> > index 4187f69f6630..e2ce60d00e8a 100644 > >>> > --- a/arch/arm/configs/imx_v6_v7_defconfig > >>> > +++ b/arch/arm/configs/imx_v6_v7_defconfig > >>> > @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y > >>> > CONFIG_SOC_LS1021A=y > >>> > CONFIG_SOC_VF610=y > >>> > CONFIG_PCI=y > >>> > +CONFIG_PCI_MSI=y > >>> > CONFIG_PCI_IMX6=y > >>> > CONFIG_SMP=y > >>> > CONFIG_PREEMPT_VOLUNTARY=y > >>> > -- > >>> > 2.6.2 > >>> > > >>> > > >>> > _______________________________________________ > >>> > linux-arm-kernel mailing list > >>> > linux-arm-kernel@lists.infradead.org > >>> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > >>> > >>> Lucas, > >>> > >>> Any thoughts on why enabling MSI on IMX6 breaks legacy interrupts? > >>> > >>> Again, many PCI devices/drivers don't support MSI and thus enabling > >>> MSI as this patch does makes this config break many PCI devices on > >>> IMX6. > >>> > >>> I have found that MSI does indeed work on the IMX6 for cards/drivers > >>> that use MSI, but for those that don't the legacy interrupts never > >>> fire regardless of going through a bridge or directly hanging off the > >>> IMX6. I assume you can confirm this on your boards/devices as well? > >>> > >> No, this seems to be an errata in the DW PCIe core. The manual states > >> that legacy IRQs and MSIs can't be used together, but I thought this > >> only applies to the EP part of the core. > >> > >> We can probably fix the simple configuration by not enabling MSI > support > >> until someone actually requests to set up an MSI IRQ, so both IRQ types > >> work when only one EP is connected. > >> I don't have any idea yet how to fix setups with a PCIe switch where > >> some connected EPs might like to use MSIs while some others can't use > >> them. > >> > >> Regards, > >> Lucas > >> > > > > Lucas, > > > > I feel a bit dumb here for forgetting about this issue and letting it > > drop, but I've just spent a day debugging an issue with the ath9k > > wireless driver only to realize it was that the ath9k card and/or > > driver doesn't support MSI interrupts and thus no longer work on > > mainline kernels that have MSI enabled. To be honest I'm not sure how > > many PCIe devices out there can't support MSI because of hardware > > limitations vs drivers that simply have not implemented it. > > > > To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes > > it such that you can't disable MSI on the IMX6. > > > > Is there some fix you can think of to make the IMX6 PCIe host > > controller raise an interrupt for cards/drivers that use legacy irq's? > > If not, then we need to allow MSI to be disabled for IMX6 and default > > it to disabled for compatibility. > > > > Joao / Jingoo, > > (Adding linux-pci to the list to pick up maintainers of other DWC PCIe > core drivers) > > Is Luca's statement that 'legacy IRQs and MSIs can't be used together' > true in general for the DW PCIe core? If any of the host controllers > using this core can't support both legacy and MSI irqs together I > still believe we shouldn't enable/require MSI as it breaks any > card/driver that only supports legacy interrupts (such as ath9k). If there are 2 DW PCIe controllers, one controller can be used for legacy and another controller can be used for MSI. But, I am not sure that one DW PCIe controller can support both MSI device and legacy interrupt device at the same time. To Joao Pinto, Will you confirm this? Or if there is anyone who knows this well, please share your knowledge. :-) Thanks. Best regards, Jingoo Han > > Regards, > > Tim
Às 9:54 PM de 4/4/2017, Jingoo Han escreveu: > On Friday, March 31, 2017 12:05 PM, Tim Harvey wrote: >> On Thu, Mar 30, 2017 at 4:42 PM, Tim Harvey <tharvey@gateworks.com> wrote: >>> On Fri, Apr 15, 2016 at 1:21 AM, Lucas Stach <l.stach@pengutronix.de> >> wrote: >>>> Am Donnerstag, den 14.04.2016, 08:13 -0700 schrieb Tim Harvey: >>>>> On Mon, Nov 30, 2015 at 9:00 AM, Lucas Stach <l.stach@pengutronix.de> >> wrote: >>>>>> This has been stable on i.MX6 for a good while now and there is no >>>>>> reason to keep it disabled, as it allows to allocate non-shared >>>>>> IRQs if several PCIe devices are connected to a single host. >>>>>> >>>>>> Signed-off-by: Lucas Stach <l.stach@pengutronix.de> >>>>>> --- >>>>>> arch/arm/configs/imx_v6_v7_defconfig | 1 + >>>>>> 1 file changed, 1 insertion(+) >>>>>> >>>>>> diff --git a/arch/arm/configs/imx_v6_v7_defconfig >> b/arch/arm/configs/imx_v6_v7_defconfig >>>>>> index 4187f69f6630..e2ce60d00e8a 100644 >>>>>> --- a/arch/arm/configs/imx_v6_v7_defconfig >>>>>> +++ b/arch/arm/configs/imx_v6_v7_defconfig >>>>>> @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y >>>>>> CONFIG_SOC_LS1021A=y >>>>>> CONFIG_SOC_VF610=y >>>>>> CONFIG_PCI=y >>>>>> +CONFIG_PCI_MSI=y >>>>>> CONFIG_PCI_IMX6=y >>>>>> CONFIG_SMP=y >>>>>> CONFIG_PREEMPT_VOLUNTARY=y >>>>>> -- >>>>>> 2.6.2 >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> linux-arm-kernel mailing list >>>>>> linux-arm-kernel@lists.infradead.org >>>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.infradead.org_mailman_listinfo_linux-2Darm-2Dkernel&d=DwICaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=yQx7ybu-JGcPPh6ZlQyxkC6_Uw62cuBKLb7o3zpK7hQ&s=o-tR0mZ5yKNTTXKX1MR7NuDLpHfvSHIjzi47YLue0aA&e= >>>>> >>>>> Lucas, >>>>> >>>>> Any thoughts on why enabling MSI on IMX6 breaks legacy interrupts? >>>>> >>>>> Again, many PCI devices/drivers don't support MSI and thus enabling >>>>> MSI as this patch does makes this config break many PCI devices on >>>>> IMX6. >>>>> >>>>> I have found that MSI does indeed work on the IMX6 for cards/drivers >>>>> that use MSI, but for those that don't the legacy interrupts never >>>>> fire regardless of going through a bridge or directly hanging off the >>>>> IMX6. I assume you can confirm this on your boards/devices as well? >>>>> >>>> No, this seems to be an errata in the DW PCIe core. The manual states >>>> that legacy IRQs and MSIs can't be used together, but I thought this >>>> only applies to the EP part of the core. >>>> >>>> We can probably fix the simple configuration by not enabling MSI >> support >>>> until someone actually requests to set up an MSI IRQ, so both IRQ types >>>> work when only one EP is connected. >>>> I don't have any idea yet how to fix setups with a PCIe switch where >>>> some connected EPs might like to use MSIs while some others can't use >>>> them. >>>> >>>> Regards, >>>> Lucas >>>> >>> >>> Lucas, >>> >>> I feel a bit dumb here for forgetting about this issue and letting it >>> drop, but I've just spent a day debugging an issue with the ath9k >>> wireless driver only to realize it was that the ath9k card and/or >>> driver doesn't support MSI interrupts and thus no longer work on >>> mainline kernels that have MSI enabled. To be honest I'm not sure how >>> many PCIe devices out there can't support MSI because of hardware >>> limitations vs drivers that simply have not implemented it. >>> >>> To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes >>> it such that you can't disable MSI on the IMX6. >>> >>> Is there some fix you can think of to make the IMX6 PCIe host >>> controller raise an interrupt for cards/drivers that use legacy irq's? >>> If not, then we need to allow MSI to be disabled for IMX6 and default >>> it to disabled for compatibility. >>> >> >> Joao / Jingoo, >> >> (Adding linux-pci to the list to pick up maintainers of other DWC PCIe >> core drivers) >> >> Is Luca's statement that 'legacy IRQs and MSIs can't be used together' >> true in general for the DW PCIe core? If any of the host controllers >> using this core can't support both legacy and MSI irqs together I >> still believe we shouldn't enable/require MSI as it breaks any >> card/driver that only supports legacy interrupts (such as ath9k). > > If there are 2 DW PCIe controllers, one controller can be used for legacy > and another controller can be used for MSI. > > But, I am not sure that one DW PCIe controller can support both MSI device > and legacy interrupt device at the same time. > > To Joao Pinto, > Will you confirm this? > Hi Jingoo, I confirm that if a RC has MSI enable, it won't support legacy interrupts. Regards, Joao > Or if there is anyone who knows this well, please share your knowledge. :-) > Thanks. > > Best regards, > Jingoo Han > >> >> Regards, >> >> Tim >
Am Mittwoch, den 05.04.2017, 13:07 +0100 schrieb Joao Pinto: [...] > >>> Lucas, > >>> > >>> I feel a bit dumb here for forgetting about this issue and letting it > >>> drop, but I've just spent a day debugging an issue with the ath9k > >>> wireless driver only to realize it was that the ath9k card and/or > >>> driver doesn't support MSI interrupts and thus no longer work on > >>> mainline kernels that have MSI enabled. To be honest I'm not sure how > >>> many PCIe devices out there can't support MSI because of hardware > >>> limitations vs drivers that simply have not implemented it. > >>> > >>> To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes > >>> it such that you can't disable MSI on the IMX6. > >>> > >>> Is there some fix you can think of to make the IMX6 PCIe host > >>> controller raise an interrupt for cards/drivers that use legacy irq's? > >>> If not, then we need to allow MSI to be disabled for IMX6 and default > >>> it to disabled for compatibility. > >>> > >> > >> Joao / Jingoo, > >> > >> (Adding linux-pci to the list to pick up maintainers of other DWC PCIe > >> core drivers) > >> > >> Is Luca's statement that 'legacy IRQs and MSIs can't be used together' > >> true in general for the DW PCIe core? If any of the host controllers > >> using this core can't support both legacy and MSI irqs together I > >> still believe we shouldn't enable/require MSI as it breaks any > >> card/driver that only supports legacy interrupts (such as ath9k). > > > > If there are 2 DW PCIe controllers, one controller can be used for legacy > > and another controller can be used for MSI. > > > > But, I am not sure that one DW PCIe controller can support both MSI device > > and legacy interrupt device at the same time. > > > > To Joao Pinto, > > Will you confirm this? > > > > Hi Jingoo, > I confirm that if a RC has MSI enable, it won't support legacy interrupts. Okay, so the only way to solve this in a generic way, that I can see at the moment is to defer MSI enable until the downstream device actually requests an MSI irq. Also we need to disable the MSI capability if any bridge device turns up during the bus topology scan, as we can have devices with conflicting requirements connected to the RC in that case. I'll cook up some patches to implement this. Regards, Lucas
On Wed, Apr 5, 2017 at 5:16 AM, Lucas Stach <l.stach@pengutronix.de> wrote: > Am Mittwoch, den 05.04.2017, 13:07 +0100 schrieb Joao Pinto: > [...] >> >>> Lucas, >> >>> >> >>> I feel a bit dumb here for forgetting about this issue and letting it >> >>> drop, but I've just spent a day debugging an issue with the ath9k >> >>> wireless driver only to realize it was that the ath9k card and/or >> >>> driver doesn't support MSI interrupts and thus no longer work on >> >>> mainline kernels that have MSI enabled. To be honest I'm not sure how >> >>> many PCIe devices out there can't support MSI because of hardware >> >>> limitations vs drivers that simply have not implemented it. >> >>> >> >>> To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes >> >>> it such that you can't disable MSI on the IMX6. >> >>> >> >>> Is there some fix you can think of to make the IMX6 PCIe host >> >>> controller raise an interrupt for cards/drivers that use legacy irq's? >> >>> If not, then we need to allow MSI to be disabled for IMX6 and default >> >>> it to disabled for compatibility. >> >>> >> >> >> >> Joao / Jingoo, >> >> >> >> (Adding linux-pci to the list to pick up maintainers of other DWC PCIe >> >> core drivers) >> >> >> >> Is Luca's statement that 'legacy IRQs and MSIs can't be used together' >> >> true in general for the DW PCIe core? If any of the host controllers >> >> using this core can't support both legacy and MSI irqs together I >> >> still believe we shouldn't enable/require MSI as it breaks any >> >> card/driver that only supports legacy interrupts (such as ath9k). >> > >> > If there are 2 DW PCIe controllers, one controller can be used for legacy >> > and another controller can be used for MSI. >> > >> > But, I am not sure that one DW PCIe controller can support both MSI device >> > and legacy interrupt device at the same time. >> > >> > To Joao Pinto, >> > Will you confirm this? >> > >> >> Hi Jingoo, >> I confirm that if a RC has MSI enable, it won't support legacy interrupts. > > Okay, so the only way to solve this in a generic way, that I can see at > the moment is to defer MSI enable until the downstream device actually > requests an MSI irq. > > Also we need to disable the MSI capability if any bridge device turns up > during the bus topology scan, as we can have devices with conflicting > requirements connected to the RC in that case. > > I'll cook up some patches to implement this. > Lucas, Any thoughts yet? I'll likely want to backport this to stable although the restructuring to drivers/pci/dwc and subsequent changes since 4.10 will likely require a re-written patch. Best regards, Tim
Hi Tim, Am Dienstag, den 11.04.2017, 09:05 -0700 schrieb Tim Harvey: > On Wed, Apr 5, 2017 at 5:16 AM, Lucas Stach <l.stach@pengutronix.de> wrote: > > Am Mittwoch, den 05.04.2017, 13:07 +0100 schrieb Joao Pinto: > > [...] > >> >>> Lucas, > >> >>> > >> >>> I feel a bit dumb here for forgetting about this issue and letting it > >> >>> drop, but I've just spent a day debugging an issue with the ath9k > >> >>> wireless driver only to realize it was that the ath9k card and/or > >> >>> driver doesn't support MSI interrupts and thus no longer work on > >> >>> mainline kernels that have MSI enabled. To be honest I'm not sure how > >> >>> many PCIe devices out there can't support MSI because of hardware > >> >>> limitations vs drivers that simply have not implemented it. > >> >>> > >> >>> To make matters worse 3ee803641e76bea76ec730c80dcc64739a9919ff makes > >> >>> it such that you can't disable MSI on the IMX6. > >> >>> > >> >>> Is there some fix you can think of to make the IMX6 PCIe host > >> >>> controller raise an interrupt for cards/drivers that use legacy irq's? > >> >>> If not, then we need to allow MSI to be disabled for IMX6 and default > >> >>> it to disabled for compatibility. > >> >>> > >> >> > >> >> Joao / Jingoo, > >> >> > >> >> (Adding linux-pci to the list to pick up maintainers of other DWC PCIe > >> >> core drivers) > >> >> > >> >> Is Luca's statement that 'legacy IRQs and MSIs can't be used together' > >> >> true in general for the DW PCIe core? If any of the host controllers > >> >> using this core can't support both legacy and MSI irqs together I > >> >> still believe we shouldn't enable/require MSI as it breaks any > >> >> card/driver that only supports legacy interrupts (such as ath9k). > >> > > >> > If there are 2 DW PCIe controllers, one controller can be used for legacy > >> > and another controller can be used for MSI. > >> > > >> > But, I am not sure that one DW PCIe controller can support both MSI device > >> > and legacy interrupt device at the same time. > >> > > >> > To Joao Pinto, > >> > Will you confirm this? > >> > > >> > >> Hi Jingoo, > >> I confirm that if a RC has MSI enable, it won't support legacy interrupts. > > > > Okay, so the only way to solve this in a generic way, that I can see at > > the moment is to defer MSI enable until the downstream device actually > > requests an MSI irq. > > > > Also we need to disable the MSI capability if any bridge device turns up > > during the bus topology scan, as we can have devices with conflicting > > requirements connected to the RC in that case. > > > > I'll cook up some patches to implement this. > > > > Lucas, > > Any thoughts yet? I'll likely want to backport this to stable although > the restructuring to drivers/pci/dwc and subsequent changes since 4.10 > will likely require a re-written patch. I have a fix for this, that I'm currently testing on different setups. I'll probably send it out in a few hours. Regards, Lucas
diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig index 4187f69f6630..e2ce60d00e8a 100644 --- a/arch/arm/configs/imx_v6_v7_defconfig +++ b/arch/arm/configs/imx_v6_v7_defconfig @@ -45,6 +45,7 @@ CONFIG_SOC_IMX7D=y CONFIG_SOC_LS1021A=y CONFIG_SOC_VF610=y CONFIG_PCI=y +CONFIG_PCI_MSI=y CONFIG_PCI_IMX6=y CONFIG_SMP=y CONFIG_PREEMPT_VOLUNTARY=y
This has been stable on i.MX6 for a good while now and there is no reason to keep it disabled, as it allows to allocate non-shared IRQs if several PCIe devices are connected to a single host. Signed-off-by: Lucas Stach <l.stach@pengutronix.de> --- arch/arm/configs/imx_v6_v7_defconfig | 1 + 1 file changed, 1 insertion(+)