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Subject[PATCH 1/3] hwmon (occ): Store error condition for rate-limited polls
Date
The OCC driver limits the rate of sending poll commands to the OCC. If a
user reads a hwmon entry after a poll response resulted in an error and
is rate-limited, the error is invisible to the user. Fix this by storing
the last error and returning that in the rate-limited case.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
drivers/hwmon/occ/common.c | 4 ++++
drivers/hwmon/occ/common.h | 3 ++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
index 9d197e9..13a6290 100644
--- a/drivers/hwmon/occ/common.c
+++ b/drivers/hwmon/occ/common.c
@@ -141,6 +141,7 @@ static int occ_poll(struct occ *occ)
/* mutex should already be locked if necessary */
rc = occ->send_cmd(occ, cmd);
if (rc) {
+ occ->last_error = rc;
if (occ->error_count++ > OCC_ERROR_COUNT_THRESHOLD)
occ->error = rc;

@@ -149,6 +150,7 @@ static int occ_poll(struct occ *occ)

/* clear error since communication was successful */
occ->error_count = 0;
+ occ->last_error = 0;
occ->error = 0;

/* check for safe state */
@@ -210,6 +212,8 @@ int occ_update_response(struct occ *occ)
if (time_after(jiffies, occ->last_update + OCC_UPDATE_FREQUENCY)) {
rc = occ_poll(occ);
occ->last_update = jiffies;
+ } else {
+ rc = occ->last_error;
}

mutex_unlock(&occ->lock);
diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h
index ed2cf42..fc13f3c 100644
--- a/drivers/hwmon/occ/common.h
+++ b/drivers/hwmon/occ/common.h
@@ -106,7 +106,8 @@ struct occ {
struct attribute_group group;
const struct attribute_group *groups[2];

- int error; /* latest transfer error */
+ int error; /* final transfer error after retry */
+ int last_error; /* latest transfer error */
unsigned int error_count; /* number of xfr errors observed */
unsigned long last_safe; /* time OCC entered "safe" state */

--
2.7.4
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