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SubjectRe: [PATCH] r8152: fix lockup when runtime PM is enabled
On Tue, Dec 08, 2015 at 03:18:59AM +0000, Hayes Wang wrote:
> Peter Wu
> > Sent: Tuesday, December 08, 2015 12:59 AM
> [...]
> > + if (tp->netdev->flags & IFF_UP) {
>
> Maybe you could just replace the checking of netif_running(tp->netdev)
> with this.

Simply replacing netif_running by IFF_UP does not work, it hangs during
close when the device is suspended. This patch is correct, but I have a
v2 patch that moves rtl_runtime_suspend_enable from close to suspend.

This is the evaluated scenario (run = netif_running, up = IFF_UP set):

# suspended before open
suspend (run=0, up=0)
open (run=1)
resume (run=1, up=0) <-- fixed by patch
(open ends)

# while up
suspend (run=1, up=1)
resume (run=1, up=1) <-- no issue, values match
suspend (run=1, up=1)

# close while suspended
close (run=0, up=1)
resume (run=0, up=1) <-- fixed in patch v2
(close cont and ends) <-- rtl_runtime_suspend_enable removed in v2
suspend (run=0, up=0)

# while down
resume (run=0, up=0)
suspend (run=0, up=0)

# open while suspended, open fails
open (run=1)
resume (run=1, up=0) <-- fixed by patch
(open fails)
suspend (run=0, up=0)

> Excuse me. I have a question. Before the open() is finished, the
> netif_running() would be true, but the IFF_UP wouldn't be set. Is it
> right?

That is right, this happens behind the scenes:

# open
netif_running = true
open()
if open succeeded
set IFF_UP
else
netif_running = false

# close
netif_running = false
close()
clear IFF_UP
--
Kind regards,
Peter Wu
https://lekensteyn.nl


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