On Wed, 6 Apr 2016 11:03:16 -0700 Brian Norris <computersforpeace@xxxxxxxxx> wrote: > On Tue, Apr 05, 2016 at 04:51:20PM -0300, Ezequiel Garcia wrote: > > Due to the way the 'nand-disk' LED trigger is implemented, > > it currently does not work correctly for all NAND drivers. > > > > This is somewhat related to an old thread, where we discussed > > the addition of an "mtd" LED trigger. See: > > > > http://www.spinics.net/lists/linux-leds/msg01181.html > > > > My question is: > > > > * given that nobody has complained about "nand-disk" > > working on just some NAND drivers, and... > > * given that nobody has complained (except that 2013 patch) > > about lacking a generic MTD LED trigger... > > > > Does it make any sense to have such a trigger at all? > > In other words, should we simply get rid of "nand-disk" trigger? > > I don't have much opinion about the LED trigger, except that it'd be > nice if it either worked consistently or was removed. > > > In case the answer is "We want to keep some LED trigger", > > then here's a patch for you to f̶l̶a̶m̶e̶ review: > > > > From 88c7102bb67056b443da323bd3e28b60aca948a2 Mon Sep 17 00:00:00 2001 > > From: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx> > > Date: Sat, 2 Apr 2016 18:35:50 -0300 > > Subject: [PATCH] leds: trigger: Introduce a MTD (NAND/NOR) trigger > > > > This commit introduces a MTD trigger for flash (NAND/NOR) device > > activity. The implementation is copied from IDE disk. > > > > This deprecates the "nand-disk" LED trigger, but for backwards > > compatibility, we still keep the "nand-disk" trigger around. > > > > The motivation for deprecating the "nand-disk" LED trigger is that > > it only works for NAND drivers, whereas the "mtd" LED trigger > > is more generic (in fact, "nand-disk" currently only works for > > certain NAND drivers). > > > > TODO: Measure how the trigger affects MTD I/O performance. > > It should be cheap because the blink is deferred, but still > > it makes sense to provide some hard numbers. > > > > Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx> > > [...] > > Notably, your patch changes the behavior pretty significantly. Instead > of triggering for individual NAND wait periods (very fine-grained) you > only trigger for entire write/read/erase operations. Hm, I don't think the blinking frequency can be considered a stable ABI :-). Anyway, most of the time, read/write coming from FS are done on a per-page basis (except for the UBI/UBIFS maintenance operations), so it should pretty much match the existing behavior. > That may be OK, > especially if it's modelled after IDE. > > I'd also note that you missed a few APIs (e.g., mtd_{read,write}_oob()). Yep, I forgot to mention that in my review. -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
