On Wed, Dec 09, 2015 at 10:54:38AM -0800, Peter Crosthwaite wrote: > On Wed, Dec 9, 2015 at 10:17 AM, Andrew Baumann > <andrew.baum...@microsoft.com> wrote: > >> From: Peter Crosthwaite [mailto:crosthwaitepe...@gmail.com] > >> Sent: Tuesday, 8 December 2015 23:40 > >> On Tue, Dec 8, 2015 at 10:19 PM, Andrew Baumann > >> <andrew.baum...@microsoft.com> wrote: > >> >> From: Peter Crosthwaite [mailto:crosthwaitepe...@gmail.com] > >> > I do not observe this behaviour on the real Pi2 (and it breaks UEFI). The > >> hardware semantics appear to be "if the command generates a response, > >> but you didn't want to see it, we'll successfully complete the command and > >> ignore the response", whereas the sdhci implementation raises an error for > >> this as well as signalling completion. I have read the "SD Specifications > >> Part A2 > >> SD Host Controller Simplified Specification Version 2.00", but did not find > >> anything describing this case, so it could be that this is open to > >> interpretation. > >> (It could also be specified in SDHC v3.) The specific error also seems odd > >> -- my > >> understanding is that a "command index" error means that the index in the > >> response didn't match the index of the issued command, but that's hardly > >> what is happening here.
FYI the SDHCI v3 spec is available online. Confusingly, it's listed as an addendum instead of explicitly as the sdhci spec. The file is partA2_300.pdf . -Kevin
