On 05/23/2013 01:54 PM, David Hauweele wrote: > 2013/5/23 Alan Ott <a...@signal11.us>: >> On 5/22/13 4:32 PM, David Hauweele wrote: >>> >>> I cannot use level-triggered interrupts with GPIO on the RPi, so I >>> cannot test this specific patch. >> >> >> Is there another interrupt line you can tie into which does support >> level-trigger interrupts (INT0 or something)? > > According to the datasheet it should be possible but the bcm2708 port > does not support it. I've been told that we shouldn't use level-triggered > interrupts in the first place.
Who is "we," and why shouldn't we use level-triggered interrupts? The CPU needs to detect whatever type of interrupt the attached hardware generates. > >> >> >>> However I agree with the idea of level-triggered interrupts, that >>> would fix all major problems related to missed interrupts. >>> >>> Beside this I'm running a ping -f since more than two hours now and it >>> seems to work well. >>> >> >> So that surprises me. I thought level-trigger interrupts were the thing that >> would fix this problem, and if you're not running with that patch, you just >> have the INIT_COMPLETION() fix (which you said didn't fix your issue) and >> the threaded interrupts patch, which I was fairly sure I had determined >> wasn't fixing any actual race-condition-related problems. > > I should have been more clear about this. I've tested [PATCH 1/3] > which fixes the race condition with tx_complete. That is the > INIT_COMPLETION() fix. But it is still possible to miss an interrupt, > perhaps it just took longer this time. I ran the test again today and > it failed after 30 minutes. > > I did not test [PATCH 2/3], that is the threaded IRQ. Instead I > removed interrupt enable/disable from the IRQ handler and the > workqueue. Without this the driver would fail within seconds of a ping > -f. Without what? What do you mean by "without this?" Without the enable/disable, or without the change that removes the enable/disable? > Have you observed this too ? Perhaps this problem is specific to > the bcm2708 port. > What I observe right now is that it seems to work great (ping -f for 6.5 hours) when using the three patches in this patch set on a BeagleBone. > >> >> I'm glad, but surprised that you're no longer seeing issues. >> >> Alan. >> >> >>> >>> 2013/5/22 Alan Ott <a...@signal11.us>: >>>> >>>> On 05/21/2013 10:01 PM, Alan Ott wrote: >>>>> >>>>> David Hauweele noticed that the mrf24j40 would hang arbitrarily after >>>>> some >>>>> period of heavy traffic. Two race conditions were discovered, and the >>>>> driver was changed to use threaded interrupts, since the enable/disable >>>>> of >>>>> interrupts in the driver has recently been a lighning rod whenever >>>>> issues >>>>> arise related to interrupts (costing engineering time), and since >>>>> threaded >>>>> interrupts are the right way to do it. >>>>> >>>>> Alan Ott (3): >>>>> mrf24j40: Move INIT_COMPLETION() to before packet transmission >>>>> mrf24j40: Use threaded IRQ handler >>>>> mrf24j40: Use level-triggered interrupts >>>>> >>>>> drivers/net/ieee802154/mrf24j40.c | 31 +++++++++---------------------- >>>>> 1 file changed, 9 insertions(+), 22 deletions(-) >>>> >>>> >>>> I forgot to add, I ran ping -f both ways all afternoon (6.5 hours), and >>>> it seems solid. >>>> >> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
