> -----Original Message----- > From: Daniel P. Berrangé [mailto:berra...@redhat.com] > Sent: Monday, February 24, 2020 8:36 PM > To: miaoyubo <miaoy...@huawei.com> > Cc: peter.mayd...@linaro.org; m...@redhat.com; qemu-devel@nongnu.org; > Xiexiangyou <xiexiang...@huawei.com>; shannon.zha...@gmail.com; > imamm...@redhat.com > Subject: Re: [RFC 2/2] pci-expender-bus:Add pcie-root-port to pxb-pcie > under arm. > > On Sat, Feb 15, 2020 at 08:59:28AM +0000, miaoyubo wrote: > > > > > -----Original Message----- > > > From: Daniel P. Berrangé [mailto:berra...@redhat.com] > > > Sent: Friday, February 14, 2020 6:25 PM > > > To: miaoyubo <miaoy...@huawei.com> > > > Cc: peter.mayd...@linaro.org; shannon.zha...@gmail.com; > > > imamm...@redhat.com; qemu-devel@nongnu.org; Xiexiangyou > > > <xiexiang...@huawei.com>; m...@redhat.com > > > Subject: Re: [RFC 2/2] pci-expender-bus:Add pcie-root-port to > > > pxb-pcie under arm. > > > > > > On Fri, Feb 14, 2020 at 07:25:43AM +0000, miaoyubo wrote: > > > > > > > > > -----Original Message----- > > > > > From: Daniel P. Berrangé [mailto:berra...@redhat.com] > > > > > Sent: Thursday, February 13, 2020 9:52 PM > > > > > To: miaoyubo <miaoy...@huawei.com> > > > > > Cc: peter.mayd...@linaro.org; shannon.zha...@gmail.com; > > > > > imamm...@redhat.com; qemu-devel@nongnu.org; Xiexiangyou > > > > > <xiexiang...@huawei.com>; m...@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 <miaoy...@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. > > > > > > > > > > Thanks for replying. Currently, on x86_64, pxb-pcie devices is > > presented in acpi tables but on arm, It is not, only one main host > > bridge is presented for arm in acpi dsdt tables. That's why pxb-pcie > > works on > > x86_64 but doesn't work on arm. The patch 1/2 do the work to present > > and allocate resources for pxb-pcie in arm. > > Yes, this first patch makes sense >
Thanks for the comments, the patch has been updated to v4, pls check it. > > For x86_64, if one device is going to be plugged into pxb-pcie, one > > extra pcie-root-port or pci-bridge have to be defined and plugged on > > pxb-pcie, then the device is plugged on the pcie-root-port or pci-bridge. > > > This patch 2/2 just auto defined one pcie-root-port for arm. If this > > patch abandoned, the usage of pxb-pcie would be the same with x86_64, > > therefore, to keep the same step for x86 and arm, this patch 2/2 could > > be abandonded. > > Yes, I think abandoning this patch 2 is best. Applications that know how to > use pxb-pcie on x86_64, will already do the right thing on arm too, once your > first patch is merged. > This patch has been abandoned since v3. > Regards, > Daniel > -- > |: https://berrange.com -o- > https://www.flickr.com/photos/dberrange :| > |: https://libvirt.org -o- https://fstop138.berrange.com :| > |: https://entangle-photo.org -o- > https://www.instagram.com/dberrange :| Regards, Miao