The patch titled hwmon: applesmc: fix the 'wait status failed: c != 8' problem has been added to the -mm tree. Its filename is hwmon-applesmc-fix-the-wait-status-failed-c-=-8-problem.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: hwmon: applesmc: fix the 'wait status failed: c != 8' problem From: Henrik Rydberg <rydberg@xxxxxxxxxxx> On many Macbooks since mid 2007, the Pro, C2D and Air models, applesmc fails to read some or all SMC ports. This problem has various effects, such as flooded logfiles, malfunctioning temperature sensors, accelerometers failing to initialize, and difficulties getting backlight functionality to work properly. The root of the problem seems to be the command protocol. The current code sends out a command byte, then repeatedly polls for an ack before continuing to send or recieve data. From experiments leading to this patch, it seems the command protocol never quite worked or changed so that one now sends a command byte, waits a little bit, polls for an ack, and if it fails, repeats the whole thing by sending the command byte again. This patch implements a send_command function according to the new interpretation of the protocol, and should work also for earlier models. Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx> Cc: Nicolas Boichat <nicolas@xxxxxxxxxx> Cc: Riki Oktarianto <rkoktarianto@xxxxxxxxx> Cc: Mark M. Hoffman <mhoffman@xxxxxxxxxxxxx> Cc: Jean Delvare <khali@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/hwmon/applesmc.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff -puN drivers/hwmon/applesmc.c~hwmon-applesmc-fix-the-wait-status-failed-c-=-8-problem drivers/hwmon/applesmc.c --- a/drivers/hwmon/applesmc.c~hwmon-applesmc-fix-the-wait-status-failed-c-=-8-problem +++ a/drivers/hwmon/applesmc.c @@ -191,6 +191,26 @@ static int __wait_status(u8 val) } /* + * special treatment of command port - on newer macbooks, it seems necessary + * to resend the command byte before polling the status again. Callers must + * hold applesmc_lock. + */ +static int send_command(u8 cmd) +{ + int i; + for (i = 0; i < 1000; i++) { + outb(cmd, APPLESMC_CMD_PORT); + udelay(5); + if ((inb(APPLESMC_CMD_PORT) & APPLESMC_STATUS_MASK) == 0x0c) + return 0; + udelay(5); + } + printk(KERN_WARNING "applesmc: command failed: %x -> %x\n", + cmd, inb(APPLESMC_CMD_PORT)); + return -EIO; +} + +/* * applesmc_read_key - reads len bytes from a given key, and put them in buffer. * Returns zero on success or a negative error on failure. Callers must * hold applesmc_lock. @@ -205,8 +225,7 @@ static int applesmc_read_key(const char* return -EINVAL; } - outb(APPLESMC_READ_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_READ_CMD)) return -EIO; for (i = 0; i < 4; i++) { @@ -249,8 +268,7 @@ static int applesmc_write_key(const char return -EINVAL; } - outb(APPLESMC_WRITE_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_WRITE_CMD)) return -EIO; for (i = 0; i < 4; i++) { @@ -284,8 +302,7 @@ static int applesmc_get_key_at_index(int readkey[2] = index >> 8; readkey[3] = index; - outb(APPLESMC_GET_KEY_BY_INDEX_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_GET_KEY_BY_INDEX_CMD)) return -EIO; for (i = 0; i < 4; i++) { @@ -315,8 +332,7 @@ static int applesmc_get_key_type(char* k { int i; - outb(APPLESMC_GET_KEY_TYPE_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_GET_KEY_TYPE_CMD)) return -EIO; for (i = 0; i < 4; i++) { _ Patches currently in -mm which might be from rydberg@xxxxxxxxxxx are linux-next.patch input-mousedev-distinguish-a-moving-finger-from-a-tapping-finger.patch hwmon-applesmc-specified-number-of-bytes-to-read-should-match-actual.patch hwmon-applesmc-fix-the-wait-status-failed-c-=-8-problem.patch hwmon-applesmc-prolong-status-wait.patch hwmon-applesmc-allow-for-variable-alv0-and-alv1-package-length.patch hwmon-applesmc-add-support-for-macbook-air.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html