From: Wolfgang Muees <[email protected]>
Some time ago, I have send a patch to the mmc_spi subsystem changing the error
codes. This was after a discussion with Pierre about using EINVAL only for
non-recoverable errors. This patch was accepted as
http://git.kernel.org/linus/fdd858db7113ca64132de390188d7ca00701013d
Unfortunately, several weeks later, I realized that this patch has opened a
little can of worms because there are SD cards on the market which
a) claim that they support the switch command
AND
b) refuse to execute this command if operating in SPI mode.
So, such a card would get unusuable in an embedded linux system in SPI mode,
because the init sequence terminates with an error.
This patch adds the missing error codes to the caller of the switch command
and restores the old bahaviour to fail gracefully if these commands can not
execute.
This patch should go into 2.6.31 to show up in embedded systems ASAP.
Signed-off-by: Wolfgang Muees <[email protected]>
---
diff -uprN 2_6_31_rc8/drivers/mmc/core/mmc.c 2_6_31_rc8_switch/drivers/mmc/core/mmc.c
--- 2_6_31_rc8/drivers/mmc/core/mmc.c 2009-08-28 02:59:04.000000000 +0200
+++ 2_6_31_rc8_switch/drivers/mmc/core/mmc.c 2009-09-09 14:44:45.000000000 +0200
@@ -180,11 +180,11 @@ static int mmc_read_ext_csd(struct mmc_c
err = mmc_send_ext_csd(card, ext_csd);
if (err) {
- /*
- * We all hosts that cannot perform the command
- * to fail more gracefully
- */
- if (err != -EINVAL)
+ /* If the host or the card can't do the switch,
+ * fail more gracefully. */
+ if ((err != -EINVAL)
+ && (err != -ENOSYS)
+ && (err != -EFAULT))
goto out;
/*
diff -uprN 2_6_31_rc8/drivers/mmc/core/sd.c 2_6_31_rc8_switch/drivers/mmc/core/sd.c
--- 2_6_31_rc8/drivers/mmc/core/sd.c 2009-08-28 02:59:04.000000000 +0200
+++ 2_6_31_rc8_switch/drivers/mmc/core/sd.c 2009-09-09 14:45:34.000000000 +0200
@@ -210,11 +210,11 @@ static int mmc_read_switch(struct mmc_ca
err = mmc_sd_switch(card, 0, 0, 1, status);
if (err) {
- /*
- * We all hosts that cannot perform the command
- * to fail more gracefully
- */
- if (err != -EINVAL)
+ /* If the host or the card can't do the switch,
+ * fail more gracefully. */
+ if ((err != -EINVAL)
+ && (err != -ENOSYS)
+ && (err != -EFAULT))
goto out;
printk(KERN_WARNING "%s: problem reading switch "
---
regards
i. A. Wolfgang M?es
--
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