lkml.org 
[lkml]   [2013]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: usb: why we need a msleep(5) in ehci_bus_suspend/resume
On Mon, 13 May 2013, linux fddl wrote:

> Hi,
>
> From the ehci-hub.c, I find that ehci_bus_suspend/resume have some
> code like this:
>
> if (time_before(jiffies, ehci->netx_statechange))
> msleep(5);
> ...
> ehci->next_statechange = jiffies + msec_to_jiffies(10);
>
> and
>
> if (time_before(jiffies, ehci->netx_statechange))
> msleep(5);
> ...
> ehci->next_statechange = jiffies + msec_to_jiffies(5);
>
> but I don't know why such a short sleep is needed, and why one is
> [ehci->next_statechange = jiffies + msec_to_jiffies(10)] and the other is
> [ehci->next_statechange = jiffies + msec_to_jiffies(5)],
> I googled for a long time, but it seems that there is no explanation.
>
> Anyone knows why and can give any explanation?

At this point I don't think anybody knows. The person who originally
wrote that code died a few years ago.

Alan Stern



\
 
 \ /
  Last update: 2013-05-13 17:41    [W:1.565 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site