On Thu, 21 Nov 2019, Ikjoon Jang wrote: > This patch enables hub device to override its own endpoint descriptor's > bInterval when the hub has a device node with "hub,interval" property. > > When we know reducing autosuspend delay for built-in HIDs is better for > power saving, we can reduce it to the optimal value. But if a parent hub > has a long bInterval, mouse lags a lot from more frequent autosuspend. > So this enables overriding bInterval for a hard wired hub device only > when we know that reduces the power consumption. > > Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx> > --- > drivers/usb/core/config.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c > index 5f40117e68e7..d2d9c6d6e00a 100644 > --- a/drivers/usb/core/config.c > +++ b/drivers/usb/core/config.c > @@ -6,6 +6,7 @@ > #include <linux/usb.h> > #include <linux/usb/ch9.h> > #include <linux/usb/hcd.h> > +#include <linux/usb/of.h> > #include <linux/usb/quirks.h> > #include <linux/module.h> > #include <linux/slab.h> > @@ -257,6 +258,11 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum, > memcpy(&endpoint->desc, d, n); > INIT_LIST_HEAD(&endpoint->urb_list); > > + /* device node property overrides bInterval */ > + if (usb_of_has_combined_node(to_usb_device(ddev))) > + of_property_read_u8(ddev->of_node, "hub, interval", Does it matter that this says "hub, interval" whereas the documentation says "hub,interval" (with no space character)? > + &d->bInterval); > + > /* > * Fix up bInterval values outside the legal range. > * Use 10 or 8 ms if no proper value can be guessed. Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Alan Stern
