From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCHv2 1/2] ARM: dts: socfpga: Fix SD card detect Date: Mon, 20 Oct 2014 23:41:48 +0100 Message-ID: <20141020224147.GA13670@leverpostej> References: <1413819079-17120-1-git-send-email-dinguyen@opensource.altera.com> <1413819079-17120-2-git-send-email-dinguyen@opensource.altera.com> <20141020184139.GA23062@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Doug Anderson Cc: "dinguyen-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org" , "robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org" , "galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org" , Pawel Moll , "jh80.chung-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org" , "dinh.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org" , "s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org" , Marc Zyngier List-Id: devicetree@vger.kernel.org On Mon, Oct 20, 2014 at 08:26:55PM +0100, Doug Anderson wrote: > Mark, > > On Mon, Oct 20, 2014 at 11:41 AM, Mark Rutland wrote: > > On Mon, Oct 20, 2014 at 04:31:18PM +0100, dinguyen-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org wrote: > >> From: Dinh Nguyen > >> > >> Without this patch, the booting the SOCFPGA platform would hang at the > >> SDMMC driver loading. There were 2 patches that caused this to happen: > >> > >> - Patch 9795a846e10 "mmc: dw_mmc: remove dw_mci_of_cd_gpio/wp_gpio()" removed > >> looking for "cd-gpios", since mmc_of_parse was getting called. > >> - Patch 3cf890fc42b "mmc: dw_mmc: Pass back errors from mmc_of_parse()" would > >> hang the system at the SDMMC driver loading. > > > > Regardless of which patches caused the issue, the existing DTB should > > continue to function. This is a kernel bug, not a DTB bug. > > Right. The kernel bug is that there is no "dtb fixup" stage of the > kernel to fix up old dtbs with this dtb bug. > > Said another way: > > 1. The old dtb was (possibly) not specifying the cd-gpio properly. > > 2. The kernel had a bug where it was ignoring that error. Things may > have been working because of some other side effect (maybe polling was > working). > > 3. If we fix the kernel bug, what should we do? The only sensible > thing (if we need to support old DTB with no changes) is to add a DTB > fixup stage. > > ...or did someone add that stage and I missed it? Unfortunately, we have no generic DTB fixup stage currently. What exactly was wrong with this cd-gpios description that previously allowed it to function? Can we not print a warning and fall back to the old behaviour in this case? Thanks, Mark -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html