On Tue, 28 Jun 2011 11:37:25 +0100 James Hogan <james.hogan@xxxxxxxxxx> wrote: > Hi, > > I'm trying to figure out why the broken write transfer tests in mmc_test > require the result to be -ETIMEDOUT, so that I can make dw_mmc pass > these tests. Perhaps somebody could explain. > > I can understand for reads, that the controller is waiting for the start > bit on the data lines and so it can timeout after a while if it doesn't > see any. However for writes (as far as I can glean from the physical > layer spec and a logic analyser) the data response token which is > normally sent by the card in response to a write transfer is clocked out > immediately after the data so is either there or it isn't. > > Have I misunderstood it or is -ETIMEDOUT just the error that is required > by convention when the data response token is not detected? > It's more or less by convention. ETIMEDOUT is the closest thing we have to "we expected a response from the card but got bupkis". You can find some informal definitions here: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=include/linux/mmc/core.h;h=b6718e549a510780e0f8c9a3be17e64753d6c2f5;hb=HEAD#l81 Rgds -- -- Pierre Ossman WARNING: This correspondence is being monitored by FRA, a Swedish intelligence agency. Make sure your server uses encryption for SMTP traffic and consider using PGP for end-to-end encryption.
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