Re: [PATCHv5 04/20] PCI: mobiveil: Remove the flag MSI_FLAG_MULTI_PCI_MSI

[Lorenzo Pieralisi]

On Mon, Jun 17, 2019 at 10:34:35AM +0000, Z.q. Hou wrote:

[...]

> > There is nothing obvious. Write what you are fixing in the commit log and I will
> > apply the patch, I won't write the commit log for you. Anyone should be able
> > to understand why a patch was needed by reading the commit log, it is as
> > important as writing the code itself.
> 
> With the flag MSI_FLAG_MULTI_PCI_MSI, when the Endpoint allocates
> multiple MSI, it will trigger the "WARN_ON(nr_irqs != 1);" in
> mobiveil_irq_msi_domain_alloc(), this is the issue this patch want to
> fix. 

And that's wrong. Marc explained why this controller does not support
Multi MSI and that's what should go in the commit log, triggering
a WARN_ON is the least of the problems (and the WARN_ON can even
be removed after this patch is applied), if it was used as a bandaid
to prevent allocating Multi MSI it is even more broken.

Lorenzo

> Thanks,
> Zhiqiang
> 
> > 
> > Thanks,
> > Lorenzo
> > 
> > > Thanks,
> > > Zhiqiang
> > >
> > > >
> > > > Lorenzo
> > > >
> > > > > Subbu, did you test with Endpoint supporting multi MSI?
> > > > >
> > > > > Thanks,
> > > > > Zhiqiang
> > > > >
> > > > > >
> > > > > > Thanks,
> > > > > > Lorenzo
> > > > > >
> > > > > > > Fixes: 1e913e58335f ("PCI: mobiveil: Add MSI support")
> > > > > > > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
> > > > > > > Reviewed-by: Minghuan Lian <Minghuan.Lian@xxxxxxx>
> > > > > > > ---
> > > > > > > V5:
> > > > > > >  - Corrected the subject.
> > > > > > >
> > > > > > >  drivers/pci/controller/pcie-mobiveil.c | 2 +-
> > > > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > > >
> > > > > > > diff --git a/drivers/pci/controller/pcie-mobiveil.c
> > > > > > > b/drivers/pci/controller/pcie-mobiveil.c
> > > > > > > index 563210e731d3..a0dd337c6214 100644
> > > > > > > --- a/drivers/pci/controller/pcie-mobiveil.c
> > > > > > > +++ b/drivers/pci/controller/pcie-mobiveil.c
> > > > > > > @@ -703,7 +703,7 @@ static struct irq_chip
> > > > > > > mobiveil_msi_irq_chip = {
> > > > > > >
> > > > > > >  static struct msi_domain_info mobiveil_msi_domain_info = {
> > > > > > >  	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS |
> > > > > > MSI_FLAG_USE_DEF_CHIP_OPS |
> > > > > > > -		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
> > > > > > > +		   MSI_FLAG_PCI_MSIX),
> > > > > > >  	.chip	= &mobiveil_msi_irq_chip,
> > > > > > >  };
> > > > > > >
> > > > > > > --
> > > > > > > 2.17.1
> > > > > > >