On 1/12/2017 7:15 AM, Nicholas Mc Guire wrote: > ulseep_range() uses hrtimers and provides no advantage over msleep() > for larger delays. Fix up the 100ms delays here passing the adjusted "min" > value to msleep(). This helps reduce the load on the hrtimer subsystem. > > Link: https://urldefense.proofpoint.com/v2/url?u=http-3A__lkml.org_lkml_2017_1_11_377&d=DgIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=U3o8uKoKhWme5_V9D-eeCkB11BFwt4KvWztBgdE9ZpA&m=dvQDbbH_QF2kZjARIDPimFAK95z8eOnw04feJuHCrJg&s=Prc0m1oUG4u8n8TFK-fdgzitMzE2ep6pM3L6y_DQeRs&e= > Fixes: commit 2938fc63e0c2 ("usb: dwc2: Properly account for the force mode delays") > Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx> > --- > Problem was found by cocinelle script. > > Note that this originally was an msleep(25) then commit 2938fc63e0c2 > ("usb: dwc2: Properly account for the force mode delays") changed this > to usleep_range(100000,110000) with the comment in the function head: > <snip> > After clearing the bits, wait up to 100 ms to account for any > potential IDDIG filter delay... > <snip> > but without explaining why the API was switched to usleep_range() here > It does not look like there is any reason for using a high resolution > timer here - the stated requirement is clearly satisfied by msleep(100) > as well. But it originally was usleep_range(150000, 160000) in > commit 09c96980dc72 ("usb: dwc2: Add functions to set and clear force mode") > so not sure if I am not overlooking some reason for the highrestimer here ? > > This needs to be clarified by someone that knows the details and history > of this device/driver. > > Patch was compile tested with: x86_64_defconfig + CONFIG_USB_DWC2 > > Patch is aginast 4.10-rc3 (localversion-next is next-20170112) > > drivers/usb/dwc2/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c > index 11d8ae9..439a21b 100644 > --- a/drivers/usb/dwc2/core.c > +++ b/drivers/usb/dwc2/core.c > @@ -455,7 +455,7 @@ void dwc2_clear_force_mode(struct dwc2_hsotg *hsotg) > dwc2_writel(gusbcfg, hsotg->regs + GUSBCFG); > > if (dwc2_iddig_filter_enabled(hsotg)) > - usleep_range(100000, 110000); > + msleep(100); > } > > /* > +Felipe Acked-by: John Youn <johnyoun@xxxxxxxxxxxx> John -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
