Messages in this thread | | | Date | Mon, 16 Jun 2014 20:50:17 -0700 | From | Sören Brinkmann <> | Subject | Re: [PATCH] net/cadence/macb: clear interrupts simply and correctly |
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On Tue, 2014-06-17 at 11:38AM +0900, Jongsung Kim wrote: > On 06/16/2014 11:56 PM, Sören Brinkmann wrote: > > On Mon, 2014-06-16 at 02:00PM +0900, Jongsung Kim wrote: > >> On 06/13/2014 12:44 AM, Sören Brinkmann wrote: > >>> This is now clearing all IRQ flags which is probably not what we want > >>> here. This is handling RX only. We still want the non-RX interrupts to go to > >>> the actual interrupt service routing. > >> > >> The ISR(Interrupt Status Register) is read only in the interrupt service > >> routine, macb_interrupt. But is partially cleared here and there. Further > >> handler-functions decide jobs to be done by reading/checking other status > >> registers. (e.g., TSR, RSR) So, clearing the ISR after reading looks not > >> a bad idea. > > > > But you are clearing _all_ interrupt flags in the RX NAPI handler. > > Doesn't that mean we might miss certain events? > > Please inspect my patch again. What I did in the macb_poll is removing > statements clearing the Rx-complete interrupt, not clearing all the > interrupts.
Oh, you're right. I misread the patch, sorry. The call to macb_read_isr was already a different hunk. Why is clearing those bits removed? It's probably not a big hit, but it might result in a pointless interrupt which could be avoided. But it should probably clear all RX interrupts - MACB_RX_INT_FLAGS - instead of just RCOMP. For clear-on-read implementations it shouldn't make a difference.
And in the if-condition in that new helper, I'd add '&& status' to avoid writing back zeros.
Thanks, Sören -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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