On 10/12/2016 04:58 PM, Ulf Hansson wrote: > On 12 October 2016 at 09:09, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: >> On 05/10/16 14:55, Ravikumar wrote: >>> Hi Shawn, >>> >>> >>> On Wednesday 05 October 2016 03:07 PM, Shawn Lin wrote: >>>> Hi Ravikumar, >>>> >>>> + Alex, >>>> >>>> 在 2016/10/3 18:43, Ravikumar Kattekola 写道: >>>>> Hi all, >>>>> I’ve seen an eMMC failure due to pending background operations on a >>>>> certain OMAP device since bkops enable bit was not set. >> >> It is not clear what you are talking about. BKOPS_EN is >> one-time-programmable so you can just set when the device is provisioned. >> >> However BKOPS_EN does not really enable background operations. It is an >> indication from the host to the card about whether the card may delay >> maintenance operations. The definition is: >> >> "This field allows the host to indicate to the device if it is expected to >> periodically manually start background operations by writing to the >> BKOPS_START field." >> >> Currently the kernel does not do periodic background operations, so having >> the kernel set BKOPS_EN would not make sense - even if it wasn't >> one-time-programmable. > > Agree! > > However, in cases when the BKOPS_EN bit has been set (in one way or > the other), this do becomes a problem as we currently only supports > urgent background operations. > Perhaps we should print a warning when BKOPS_EN is set during card > initialization, as this isn't currently supported. When i had added the bkops features, i remembered that discussed about this. (set BKOPS_EN from kernel..or not..) When enable the bkops_en by default, there should be a problem... (I'm not sure..but at that time..Chris had wanted to remove the enabling bkops by default.) For just understanding..i added the changelog for my bkops patch. https://patchwork.kernel.org/patch/1466501/ > >> >>>>> Further investigation showed me that someone already posted patch to >>>>> enable Background operations in kernel based on a host capability check >>>>> (Caps2 & BK_OPS_EN) >>>>> but was turned down quoting that it should be enabled from user space >>>>> using mmc-utils. >>>>> >>>>> Enabling this would add one additional check for exception event in the >>>>> response R1 or R1B (only on hosts that explicitly set BK_OPS_EN in caps2). >>>>> But not enabling this could lead to a system failure especially when the >>>>> Filesystem is on eMMC and the card stops responding due to pending >>>>> critical bkops. >> >> Yes the kernel only does urgent background operations if BKOPS_EN is set. >> You seem to be suggesting that the cards are violating the specification by >> delaying maintenance operations even though they are not allowed to because >> BKOPS_EN is not set. Is that the case? >> > > If this is the case, the solution would probably be to actually set > the BKOPS_EN bit from the kernel, perhaps via using a card quirk. > > Although, to do that, we first need to add proper background > operations support. I guess that is what Alex intends to do here [1]. > > [...] > > [1] > http://www.spinics.net/lists/linux-mmc/msg38952.html > > Kind regards > Uffe > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
