| Message ID | 20250313-mhi_bw_up-v2-1-869ca32170bf@oss.qualcomm.com |
|---|---|
| State | New |
| Headers | show |
| Series | bus: mhi: host: Add support for mhi bus bw | expand |
On Thu, Mar 13, 2025 at 12:00:01PM -0500, Bjorn Helgaas wrote: > [+cc Bartosz since this is related to pwrctrl] > > On Thu, Mar 13, 2025 at 05:10:08PM +0530, Krishna Chaitanya Chundru wrote: > > If the link is not up till the pwrctl drivers enable power to endpoints > > then cur_bus_speed will not be updated with correct speed. > > > > As part of rescan, pci_bus_add_devices() will be called and as part of > > it update the link bus speed. > > > > Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> > > --- > > drivers/pci/bus.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c > > index 98910bc0fcc4..994879071d4c 100644 > > --- a/drivers/pci/bus.c > > +++ b/drivers/pci/bus.c > > @@ -432,6 +432,9 @@ void pci_bus_add_devices(const struct pci_bus *bus) > > struct pci_dev *dev; > > struct pci_bus *child; > > > > + if (bus->self) > > + pcie_update_link_speed((struct pci_bus *)bus); > > Why the cast? I guess to discard "const"? I would prefer to avoid > that if we can. > > The only existing callers of pcie_update_link_speed() are from bwctrl, > where it obviously makes sense because bwctrl manages link speed, and > from pci_set_bus_speed() in the pci_alloc_child_bus() path. > > If we call pcie_update_link_speed() here, do we still need the > pci_set_bus_speed() in pci_alloc_child_bus()? > > Bartosz, so you have any suggestions? Is there a point in pwrctrl > where it would make sense to do this, similar to what bwctrl does? > I'm not Bartosz, but I could speak for pwrctrl. This should really be part of pci_pwrctrl_notify() in pwrctrl driver. Pwrctrl driver is already getting notified with device additions and removals. So the update can be performed once the device addition happens. - Mani
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index 98910bc0fcc4..994879071d4c 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -432,6 +432,9 @@ void pci_bus_add_devices(const struct pci_bus *bus) struct pci_dev *dev; struct pci_bus *child; + if (bus->self) + pcie_update_link_speed((struct pci_bus *)bus); + list_for_each_entry(dev, &bus->devices, bus_list) { /* Skip already-added devices */ if (pci_dev_is_added(dev))
If the link is not up till the pwrctl drivers enable power to endpoints then cur_bus_speed will not be updated with correct speed. As part of rescan, pci_bus_add_devices() will be called and as part of it update the link bus speed. Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> --- drivers/pci/bus.c | 3 +++ 1 file changed, 3 insertions(+)