Re: [PATCH] can: flexcan: fix irq flooding by clearing all interrupt sources

On 12/13/2011 01:13 PM, Wolfgang Grandegger wrote:

On 12/12/2011 04:44 PM, Wolfgang Grandegger wrote:

quoted

On 12/12/2011 04:31 PM, Marc Kleine-Budde wrote:

quoted

On 12/12/2011 04:09 PM, Wolfgang Grandegger wrote:

quoted

As pointed out by Reuben Dowle and Lothar Waßmann, the TWRN_INT,
RWRN_INT, BOFF_INT interrupt sources need to be cleared as well
to avoid interrupt flooding, at least for the Flexcan on i.MX28
SOCs. Furthermore, the interrupts are only cleared, if really one
of those interrupt sources are pending (which is not the case for
rx and tx done).

CC: Reuben Dowle <redacted>
CC: Lothar Waßmann <redacted>
Signed-off-by: Wolfgang Grandegger <redacted>

Have you tested on mx25/mx35, does it have any negative side effects?
My schedule is full until Friday, sorry cannot test here.

Not yet. But it's not critical. Only the pending interrupt flags are
cleared. Maybe somebody else out there could do some testing... before I
get hold of a MX35PDK board.

I got my MX35PDK board working and can confirm, that the patch works on
a i.mx35 as well. My testing also confirms, that the ESR TWRN_INT,
RWRN_INT, FLEXCAN_ESR_BOFF_INT do not function as documented. These
flags do show up once, together with ERR_INT, and then, after clearing,
never again. Obviously a bug in the Flexcan logic. From the feedback we
can say, that only the i.MX28 does behave differently (==correctly). All
other seem to work with the current code:

 Flexcan on
 - i.mx25
 - i.mx35
 - i.mx53
 - P1010/P1020

I'm adding the patch to linux-can. I think this is a stable candidate
for v2.6.39 and newer (mx28 suport was added in 2.6.39).

Marc

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