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@xxxxxxxxxxxxx> wrote: >>> On Fri, Apr 15, 2016 at 1:21 AM, Lucas Stach <l.stach@xxxxxxxxxxxxxx> >> 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@xxxxxxxxxxxxxx> >> 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@xxxxxxxxxxxxxx> >>>>>> --- >>>>>> 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@xxxxxxxxxxxxxxxxxxx >>>>>> 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 >
