Messages in this thread | | | Date | Mon, 02 Dec 2013 16:15:54 +0100 | From | Nicolas Schichan <> | Subject | Spurious timeouts in mvmdio |
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Hi,
During 3.13-rc1 testing, I have found out that the mvmdio driver would report timeouts on the kernel console:
[ 11.011334] orion-mdio orion-mdio: Timeout: SMI busy for too long
The hardware is a MV88F6281 Kirkwood CPU. The mvmdio driver is using the irq line 46 (ge00_err).
I am inclined to believe that it is due to the fact that wait_event_timeout() is called with a timeout parameter of 1 jiffy in orion_mdio_wait_ready(). If the timer interrupt ticks right after calling wait_event_timeout(), we may end up spending much less time than MVMDIO_SMI_TIMEOUT (1 msec) in wait_event_timeout(), and as a result report a timeout as the MDIO access did not complete in such a short time.
As to how to fix this, I see two options (I don't know which one would be prefered):
- Option 1: always pass a timeout of at least 2 jiffy to wait_event_timeout(). - Option 2: switch to wait_event_hrtimeout().
I can provide patches for both options.
Regards,
-- Nicolas Schichan
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