Re: [PATCH] PCI: controller: dwc: Make PCI_IMX6 depend on PCIEPORTBUS

From: Robert Hancock <hancock@sedsystems.ca>
To: Baruch Siach <baruch@tkos.co.il>,
	Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: linux-pci@vger.kernel.org, "A.s. Dong" <aisheng.dong@nxp.com>,
	Richard Zhu <hongxing.zhu@nxp.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-imx@nxp.com,
	bhelgaas@google.com, Leonard Crestez <leonard.crestez@nxp.com>,
	cphealy@gmail.com, l.stach@pengutronix.de,
	Trent Piepho <tpiepho@impinj.com>
Subject: Re: [PATCH] PCI: controller: dwc: Make PCI_IMX6 depend on PCIEPORTBUS
Date: Thu, 6 Dec 2018 09:45:47 -0600	[thread overview]
Message-ID: <5a3543f2-fe58-221d-694f-0f98a643edfc@sedsystems.ca> (raw)
In-Reply-To: <87o99zjcsc.fsf@tkos.co.il>

On 2018-12-06 2:10 a.m., Baruch Siach wrote:
> Hi Andrey,
> 
> Adding Robert Hancock who reported[1] on a PCIe MSI issue with i.MX6.
> 
> Andrey Smirnov writes:
> 
>> Building a kernel with CONFIG_PCI_IMX6=y, but CONFIG_PCIEPORTBUS=n
>> produces a system where built-in PCIE bridge (16c3:abcd) isn't bound
>> to pcieport driver. This, in turn, results in a PCIE bus that is
>> capable of enumerating attached PCIE device, but lacks functional
>> interrupt support.
> 
> Robert, does that fix your issue?

Unfortunately, no.. in fact the situation on my setup is even worse with
CONFIG_PCIEPORTBUS enabled: Not only does MSI still not function, but
now INTx interrupts are somehow broken as well - no interrupts are
received. The IRQ information shown in /proc/interrupts is correct, but
the count remains stubbornly at 0.

So given that outcome, I don't think we should add this as a hard
dependency until we can figure out what is going on, as it seems to
regress working setups.

> 
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>> ---
>>
>> Assuming this is a reasonable dependency, shold this be done to more
>> than just i.MX6 driver?
>>
>>  drivers/pci/controller/dwc/Kconfig | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
>> index 2b139acccf32..44ededbeab85 100644
>> --- a/drivers/pci/controller/dwc/Kconfig
>> +++ b/drivers/pci/controller/dwc/Kconfig
>> @@ -92,6 +92,7 @@ config PCI_IMX6
>>  	bool "Freescale i.MX6 PCIe controller"
>>  	depends on SOC_IMX8MQ || SOC_IMX6Q || (ARM && COMPILE_TEST)
>>  	depends on PCI_MSI_IRQ_DOMAIN
>> +	depends on PCIEPORTBUS
> 
> This effectively disables PCIe in imx_v6_v7_defconfig, since
> CONFIG_PCIEPORTBUS is not enabled there. Maybe do 'select' instead?
> 
>>  	Select PCIE_DW_HOST
>>
>>  config PCIE_SPEAR13XX
> 
> baruch
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-November/614800.html
> 
> --
>      http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
> =}------------------------------------------------ooO--U--Ooo------------{=
>    - baruch@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -
> 

-- 
Robert Hancock
Senior Software Developer
SED Systems
Email: hancock@sedsystems.ca