Messages in this thread | | | From | Ohad Ben-Cohen <> | Date | Mon, 5 Dec 2011 21:37:07 +0200 | Subject | Re: [PATCH] mmc/sdio: don't allow interface to runtime-suspend until probe is finished. |
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On Mon, Dec 5, 2011 at 9:06 PM, NeilBrown <neilb@suse.de> wrote: > Challenge accepted.
cool :)
> Even if I don't find a better solution, this seems backwards. Sure the > default should be that PM is enabled, but individual board can request no > PM on MMC interfaces where it is a problem.
I somewhat tend to pick a white listing approach, so we don't keep on inflicting further pain on random sdio users (at least until we learn more about the issues at hand), but I wouldn't object black listing.
> The chip has a requirement that the reset line is held down during power-on, > and raised shortly after (I don't know exactly how short). So if you just > remove power and give it back, the chip doesn't come up properly.
Well, not according to Bing Zhao from Marvell:
http://www.mail-archive.com/linux-mmc@vger.kernel.org/msg08257.html
Though I agree that if we do find this reset line helping (and get it to work cleanly with the help of some regulator code), the solution might be much more robust.
> "It *should be* perfectly fine ..." :-)
heh, yeah :)
> We just have to make sure the bug powers up the card properly. > Maybe I need to create a virtual regulator that powers on the real regulator, > then raises the reset line. I wonder how hard that is.
Btw did you try toggling the reset line manually and see if it really helps ?
> I'll spend some more time on this and get back to you - probably next week.
Very cool, thanks a lot.
Ohad. -- 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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