Messages in this thread | | | Date | Tue, 02 Sep 2014 20:39:22 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH 15/15] tty: serial: 8250: omap: add dma support |
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On 09/01/2014 07:47 PM, Sebastian Andrzej Siewior wrote: > Comparing it with serial-omap I see the same thing: I takes approx the > same amount of data until the first one is displayed. After a lot of > "long" writes which wake the chip up from idle I manage to freeze both, > the serial-omap driver and mine driver.
So after some testing: - it happens with omap-serial as well. Especially after disabling the LED trigger for both LEDs.
- it seemed that disabling the MDR1 check whether or not we lost context made the problem appear less often but it was a trick. Even with restoring the context each time I see the same problem.
- it seems to be easier to trigger with the LED trigger switched off. However sometimes it works for 10 minutes, sometimes it triggers after one.
- I see to face two kind of "deaths": - the LED still goes on and off and the uart just does not respond even if I tell the button print something on the screen (the button also changes the frequency of the LED so I know that the button is doing something). Also from dumping the content of /proc/interrupts it seems that a wake up is made, the uart should have restored the registers.
- one where the system is dead and the LED does not blink anymore. Also my button is dead.
- disabling DMA makes the problem not go away.
- mdelay(25) in omap8250_lost_context() is long enough to drop the 403 bytes I send in my testcase. That means I see only "good" characters. With this the box remained alive for 2h. However the uart died anyway.
>> >> Regards, >> >> Tony >> >
Sebastian
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