| Message ID | 1434700666-6346-4-git-send-email-wangyijing@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Fri, Jun 19, 2015 at 03:57:46PM +0800, Yijing Wang wrote: > Msleep < 20ms can sleep for up to 20ms, see > Documentation/timers/timers-howto.txt, so we could > use usleep_range instead. > > Signed-off-by: Yijing Wang <wangyijing@huawei.com> > --- > drivers/pci/hotplug/pciehp_hpc.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c > index daf54be..4553728 100644 > --- a/drivers/pci/hotplug/pciehp_hpc.c > +++ b/drivers/pci/hotplug/pciehp_hpc.c > @@ -118,7 +118,7 @@ static int pcie_poll_cmd(struct controller *ctrl, int timeout) > } > if (timeout < 0) > break; > - msleep(10); > + usleep_range(10000, 11000); timers-howto.txt also says to use msleep for 10ms+ delays, so the guidance is a bit ambiguous. This particular delay does not need to be precise, and if we delay 20ms instead of 10ms (1/50th of a second vs 1/100th of a second), I don't think it makes any difference at all. If we *did* make a change here, I think we should use a range of at least 10ms. There's no need to tighten the wakeup time to the 1ms window between 10ms and 11ms. Any time in the range of 10ms to 50ms would probably be fine. But I don't think a change here is necessary, and it does make it a bit harder to analyze the code because we have some things in microseconds and others in milliseconds. > timeout -= 10; > } > return 0; /* timeout */ > -- > 1.7.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in
On 2015/6/20 1:12, Bjorn Helgaas wrote: > On Fri, Jun 19, 2015 at 03:57:46PM +0800, Yijing Wang wrote: >> Msleep < 20ms can sleep for up to 20ms, see >> Documentation/timers/timers-howto.txt, so we could >> use usleep_range instead. >> >> Signed-off-by: Yijing Wang <wangyijing@huawei.com> >> --- >> drivers/pci/hotplug/pciehp_hpc.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c >> index daf54be..4553728 100644 >> --- a/drivers/pci/hotplug/pciehp_hpc.c >> +++ b/drivers/pci/hotplug/pciehp_hpc.c >> @@ -118,7 +118,7 @@ static int pcie_poll_cmd(struct controller *ctrl, int timeout) >> } >> if (timeout < 0) >> break; >> - msleep(10); >> + usleep_range(10000, 11000); > > timers-howto.txt also says to use msleep for 10ms+ delays, so the guidance > is a bit ambiguous. > > This particular delay does not need to be precise, and if we delay 20ms > instead of 10ms (1/50th of a second vs 1/100th of a second), I don't think > it makes any difference at all. > > If we *did* make a change here, I think we should use a range of at least > 10ms. There's no need to tighten the wakeup time to the 1ms window between > 10ms and 11ms. Any time in the range of 10ms to 50ms would probably be > fine. > > But I don't think a change here is necessary, and it does make it a bit > harder to analyze the code because we have some things in microseconds and > others in milliseconds. OK? I got it, thanks for your explanation. Thanks! Yijing. > >> timeout -= 10; >> } >> return 0; /* timeout */ >> -- >> 1.7.1 >> > >
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index daf54be..4553728 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -118,7 +118,7 @@ static int pcie_poll_cmd(struct controller *ctrl, int timeout) } if (timeout < 0) break; - msleep(10); + usleep_range(10000, 11000); timeout -= 10; } return 0; /* timeout */
Msleep < 20ms can sleep for up to 20ms, see Documentation/timers/timers-howto.txt, so we could use usleep_range instead. Signed-off-by: Yijing Wang <wangyijing@huawei.com> --- drivers/pci/hotplug/pciehp_hpc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)