Re: [PATCH] PCI: imx6: Keep Root Port MSI capability also for i.MX6Q

[Soeren Moch <smoch@web.de>]

On 28.04.26 04:19, Hongxing Zhu wrote:
>> -----Original Message-----
>> From: Soeren Moch <smoch@web.de>
>> Sent: Monday, April 27, 2026 7:58 PM
>> To: Hongxing Zhu <hongxing.zhu@nxp.com>
>> Cc: Soeren Moch <smoch@web.de>; stable@vger.kernel.org; Manivannan
>> Sadhasivam <mani@kernel.org>; Lucas Stach <l.stach@pengutronix.de>; Bjorn
>> Helgaas <bhelgaas@google.com>; Frank Li <frank.li@nxp.com>; Fabio Estevam
>> <festevam@gmail.com>; linux-pci@vger.kernel.org; linux-arm-
>> kernel@lists.infradead.org; imx@lists.linux.dev; linux-kernel@vger.kernel.org
>> Subject: [PATCH] PCI: imx6: Keep Root Port MSI capability also for i.MX6Q
>>
>> [You don't often get email from smoch@web.de. Learn why this is important at
>> https://aka.ms/LearnAboutSenderIdentification ]
>>
>> Also on the NXP i.MX6Q chipset MSIs from the endpoints won't be received by
>> the iMSI-RX MSI controller if the Root Port MSI capability is disabled.
>>
>> Even though the Root Port MSIs won't be received by the iMSI-RX controller due
>> to design, this chipset has some weird hardware bug that prevents the endpoint
>> MSIs from reaching when the Root Port MSI capability is disabled.
>>
>> Hence, always keep the Root Port MSI capability for this chipset.
>>
>> Note that by keeping Root Port MSI capability, Root Port MSIs such as AER, PME
>> and others won't be received by default. So users need to use workarounds such
>> as passing 'pcie_pme=nomsi' cmdline param.
>>
>> Fixes: 3a4e8302e72f ("PCI: imx6: Keep Root Port MSI capability with iMSI-RX to
>> work around hardware bug")
>> Cc: <stable@vger.kernel.org> # 7.0.x
>> Signed-off-by: Soeren Moch <smoch@web.de>
> Acked-by: Richard Zhu <hongxing.zhu@nxp.com>

This patch is a regression fix for linux-7.0.
It is still not part of linux-7.2-rc1 .

Can I do something to get this merged, is something still missing from 
my side?

Thanks,
Soeren

> 
> Best Regards
> Richard Zhu
>> ---
>> Cc: Manivannan Sadhasivam <mani@kernel.org>
>> Cc: Richard Zhu <hongxing.zhu@nxp.com>
>> Cc: Lucas Stach <l.stach@pengutronix.de>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: Frank Li <Frank.Li@nxp.com>
>> Cc: Fabio Estevam <festevam@gmail.com>
>> Cc: linux-pci@vger.kernel.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: imx@lists.linux.dev
>> Cc: linux-kernel@vger.kernel.org
>>
>> Tested on a tbs2910 board [1]
>> [1] arch/arm/boot/dts/nxp/imx/imx6q-tbs2910.dts
>> ---
>>   drivers/pci/controller/dwc/pci-imx6.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
>> b/drivers/pci/controller/dwc/pci-imx6.c
>> index 6d6a1688e7eb..3d461bdef967 100644
>> --- a/drivers/pci/controller/dwc/pci-imx6.c
>> +++ b/drivers/pci/controller/dwc/pci-imx6.c
>> @@ -1865,7 +1865,8 @@ static const struct imx_pcie_drvdata drvdata[] = {
>>                  .flags = IMX_PCIE_FLAG_IMX_PHY |
>>                           IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND |
>>                           IMX_PCIE_FLAG_BROKEN_SUSPEND |
>> -                        IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
>> +                        IMX_PCIE_FLAG_SUPPORTS_SUSPEND |
>> +                        IMX_PCIE_FLAG_KEEP_MSI_CAP,
>>                  .dbi_length = 0x200,
>>                  .gpr = "fsl,imx6q-iomuxc-gpr",
>>                  .ltssm_off = IOMUXC_GPR12,
>> --
>> 2.43.0
>