From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 1/2] mmc: dw_mmc: Increase timeout to 20 seconds
Date: Sun, 13 Sep 2015 16:00:21 +0200 [thread overview]
Message-ID: <201509131600.21256.marex@denx.de> (raw)
In-Reply-To: <20150913120318.2d5e2e5d@jawa>
On Sunday, September 13, 2015 at 12:03:18 PM, Lukasz Majewski wrote:
> Hi Marek,
Hi,
[...]
> > > > Now from this thread I see that there're other reasons that might
> > > > affect length of at least write operation. In other words it
> > > > could be complicated unfortunately.
> > >
> > > My gut feeling is that proper handling of eMMC would require quite a
> > > fair mmc subsystem rework.
> >
> > Can you please elaborate ?
>
> This is only my personal guess (when taking account my previous work
> done with dw_mmc on Exynos HW)
> - I think Pantelis would have more knowledge to elaborate here.
OK
> > > > Still we need to fix regression first with virtually infinite
> > > > timeout :) I would even thing that simple revert of Marek's patch
> > > > may make sense for now.
> > >
> > > +1 - unfortunately there were some other patches applied to this
> > > particular patch. Simple revert might be a bit tricky here.
> >
> > -1 - In case the card gets removed during the DMA transfer and the
> > board doesn't have a watchdog, it will get stuck indefinitelly.
>
> I'm just wondering here - why the indefinite loop was working
> previously? Was anybody complaining (on the ML) about the problem of
> removing the SD card when some operation is ongoing?
It worked for me for all the workloads I used. Noone was complaining.
> The problem with potential removal of SD card (after booting the board)
> is with us for quite long time. Even with indefinite loop (without your
> patch) we also could "hang" the board if the SD card was removed
> during a transfer.
Which is why we should weed out the unbounded loops.
> > We
> > absolutelly don't want this sort of behavior in U-Boot. I understand
> > that this is the easiest way for everyone to achieve some sort of
> > "working" solution, but it is definitelly not the correct one. While
> > I do agree to increasing the timeout, I do not agree to unbounded
> > loops, sorry.
>
> We have agreed to not agree :-)
Yes :-)
> > > > From both points of view for keeping history
> > > > clean (compared to stacked fixes/workarounds) and from removal of
> > > > regression root cause.
> > >
> > > As I said before - +1 from me.
> >
> > As I said before, -1 from me. Btw. did anything regress in here? To
> > me, this seems like a newly discovered bug ...
>
> Yes, this is a bug. We had similar problem with Samsung's SDHCI, before
> we switched to dw_mmc. This issue is new at dw_mmc.
>
> > > > It's not that I like to have infinite loops but given previous
> > > > implementation worked fine for people in the previous U-Boot
> > > > release.
> > >
> > > Good justification
> >
> > It is never a justified to return to a potentially problematic version
>
> IMHO revering the change (before the release) is from the software
> development point of view better solution than adding some
> heuristic delta to timeout.
>
> > for the sake of getting some sort of crappy hardware operational.
>
> Unfortunately this "crappy hardware" is pervasive and we cannot do
> anything about it.
>
> To sum up (my point of view):
> 1. The best would be to revert the patch - but if simple "git revert" is
> not working then,
> 2. We should increase the timeout (with my patch) for v2015.10 release
Let's do this for the sake of crappy cards.
> 3. After release we can devise some kind of solution
> 4. It is a good topic for U-boot's minisummit discussion at Dublin
>
> Marek, Alexey, Tom, Pantelis what do you think?
I think yes.
next prev parent reply other threads:[~2015-09-13 14:00 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-28 13:50 [U-Boot] [PATCH 1/2] mmc: dw_mmc: Increase timeout to 20 seconds Lukasz Majewski
2015-08-28 13:50 ` [U-Boot] [PATCH 2/2] mmc: dw_mmc: Make timeout error visible to u-boot console Lukasz Majewski
2015-08-28 23:21 ` Simon Glass
2015-08-29 12:09 ` Lukasz Majewski
2015-08-29 15:07 ` Simon Glass
2015-09-03 12:33 ` Lukasz Majewski
2015-09-03 12:21 ` [U-Boot] [PATCH] FIX: fat: Provide correct return code from disk_{read|write} to upper layers Lukasz Majewski
2015-09-03 12:44 ` Tom Rini
2015-09-03 13:40 ` Lukasz Majewski
2015-09-03 14:18 ` Lukasz Majewski
2015-09-23 3:17 ` Stephen Warren
2015-09-23 8:40 ` Lukasz Majewski
2015-09-25 5:47 ` Stephen Warren
2015-09-09 7:02 ` Lukasz Majewski
2015-09-17 14:44 ` Lukasz Majewski
2015-09-12 12:51 ` [U-Boot] " Tom Rini
2015-08-28 21:55 ` [U-Boot] [PATCH 1/2] mmc: dw_mmc: Increase timeout to 20 seconds Marek Vasut
2015-08-29 11:55 ` Lukasz Majewski
2015-08-29 13:52 ` Marek Vasut
2015-08-29 16:38 ` Lukasz Majewski
2015-08-29 19:19 ` Marek Vasut
2015-09-01 11:19 ` Lukasz Majewski
2015-09-01 11:33 ` Marek Vasut
2015-09-01 15:25 ` Lukasz Majewski
2015-09-01 15:35 ` Marek Vasut
2015-09-01 16:22 ` Pantelis Antoniou
2015-09-02 8:06 ` Marek Vasut
2015-09-09 7:01 ` Lukasz Majewski
2015-09-09 11:34 ` Marek Vasut
2015-09-11 17:20 ` Alexey Brodkin
2015-09-11 21:45 ` Lukasz Majewski
2015-09-12 16:13 ` Marek Vasut
2015-09-13 10:03 ` Lukasz Majewski
2015-09-13 14:00 ` Marek Vasut [this message]
2015-09-14 10:15 ` Alexey Brodkin
2015-09-14 11:22 ` Lukasz Majewski
2015-09-14 13:36 ` Marek Vasut
2015-09-17 14:43 ` Lukasz Majewski
2015-09-18 0:31 ` Tom Rini
2015-09-18 7:32 ` Lukasz Majewski
2015-09-18 8:07 ` Przemyslaw Marczak
2015-09-18 19:27 ` Tom Rini
2015-09-21 15:32 ` Pantelis Antoniou
2015-09-14 10:30 ` Alexey Brodkin
2015-09-14 11:15 ` Przemyslaw Marczak
2015-09-14 10:33 ` Przemyslaw Marczak
2015-09-25 16:25 ` [U-Boot] [PATCH] mmc: dw_mmc: Increase timeout to 4 minutes (as in Linux kernel) Lukasz Majewski
2015-09-28 13:43 ` Przemyslaw Marczak
2015-09-28 21:08 ` Tom Rini
2015-09-28 21:08 ` [U-Boot] " Tom Rini
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