Re: [RFC 2/2] pci-expender-bus:Add pcie-root-port to pxb-pcie under arm.

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Feb 14, 2020 at 07:25:43AM +0000, miaoyubo wrote:
> 
> > -----Original Message-----
> > From: Daniel P. Berrangé [mailto:berrange@redhat.com]
> > Sent: Thursday, February 13, 2020 9:52 PM
> > To: miaoyubo <miaoyubo@huawei.com>
> > Cc: peter.maydell@linaro.org; shannon.zhaosl@gmail.com;
> > imammedo@redhat.com; qemu-devel@nongnu.org; Xiexiangyou
> > <xiexiangyou@huawei.com>; mst@redhat.com
> > Subject: Re: [RFC 2/2] pci-expender-bus:Add pcie-root-port to pxb-pcie
> > under arm.
> > 
> > On Thu, Feb 13, 2020 at 03:49:52PM +0800, Yubo Miao wrote:
> > > From: miaoyubo <miaoyubo@huawei.com>
> > >
> > > Since devices could not directly plugged into pxb-pcie, under arm, one
> > > pcie-root port is plugged into pxb-pcie. Due to the bus for each
> > > pxb-pcie is defined as 2 in acpi dsdt tables(one for pxb-pcie, one for
> > > pcie-root-port), only one device could be plugged into one pxb-pcie.
> > 
> > What is the cause of this arm specific requirement for pxb-pcie and more
> > importantly can be fix it so that we don't need this patch ?
> > I think it is highly undesirable to have such a per-arch difference in
> > configuration of the pxb-pcie device. It means any mgmt app which already
> > supports pxb-pcie will be broken and need to special case arm.
> > 
> 
> Thanks for your reply, Without this patch, the pxb-pcie is also useable, 
> however, one extra pcie-root-port or pci-bridge or something else need 
> to be defined by mgmt. app. This patch will could be abandoned.

That's not really answering my question. IIUC, this pxb-pcie device
works fine on x86_64, and I want to know why it doesn't work on arm ?
Requiring different setups by the mgmt apps is not at all nice because
it will inevitably lead to broken arm setups. x86_64 gets far more testing
& usage, developers won't realize arm is different.



Regards,
Daniel
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