Re: [PATCH] irqchip: fix the config HISILICON_IRQ_MBIGEN dependency error.

[Jiancheng Xue <xuejiancheng@hisilicon.com>]

Hi Marc，

On 2016/6/21 18:36, Marc Zyngier wrote:
> On 21/06/16 10:26, Jiancheng Xue wrote:
>> This patch fixes the compiling error caused when
>> config HISILICON_IRQ_MBIGEN is selected but
>> PCI_MSI is not seleted.
>>
>> Signed-off-by: Jiancheng Xue <xuejiancheng@hisilicon.com>
>> ---
>>  drivers/irqchip/Kconfig | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
>> index fa33c50..23dcf3e 100644
>> --- a/drivers/irqchip/Kconfig
>> +++ b/drivers/irqchip/Kconfig
>> @@ -110,7 +110,7 @@ config DW_APB_ICTL
>>  config HISILICON_IRQ_MBIGEN
>>  	bool
>>  	select ARM_GIC_V3
>> -	select ARM_GIC_V3_ITS
>> +	select ARM_GIC_V3_ITS if PCI_MSI
>>  	select GENERIC_MSI_IRQ_DOMAIN
> 
> How can this be correct? The MBIGEN uses platform MSI (not PCI) and
> relies on the ITS (it doesn't work without it). It seems that you're
> papering over another issue.
> 
Sorry. I am not familiar with this part. But I encountered errors when
I compiled. I think there may be some problems about dependency.

In this Kconfig file

config ARM_GIC_V3_ITS
        bool
        select PCI_MSI_IRQ_DOMAIN

config HISILICON_IRQ_MBIGEN
  	bool
 	select ARM_GIC_V3
	select ARM_GIC_V3_ITS
  	select GENERIC_MSI_IRQ_DOMAIN

In the file drivers/pci/Kconfig

config PCI_MSI_IRQ_DOMAIN
        bool
        depends on PCI_MSI
        select GENERIC_MSI_IRQ_DOMAIN

We can see if the HISILICON_IRQ_MBIGEN is selected, the ARM_GIC_V3_ITS and
PCI_MSI_IRQ_DOMAIN will be selected. But PCI_MSI_IRQ_DOMAIN depends on
PCI_MSI. If PCI_MSI is not selected, it will cause a compiling error like this
"drivers/irqchip/irq-gic-v3-its-pci-msi.c:52:12: error: implicit declaration of function 'pci_msi_vec_count' [-Werror=implicit-function-declaration]
  msi = max(pci_msi_vec_count(pdev), 0);"

I found many other options which need ARM_GIC_V3_ITS or PCI_MSI_IRQ_DOMAIN
were configured like below:
select ARM_GIC_V3_ITS if PCI_MSI
or
select GENERIC_MSI_IRQ_DOMAIN if PCI_MSI

Regards,
Jiancheng