Re: [PATCH V3 13/18] coresight: tmc: make sysFS and Perf mode mutually exclusive

From: Suzuki K Poulose
Date: Mon Apr 25 2016 - 10:52:13 EST


On 25/04/16 15:48, Mathieu Poirier wrote:
On 25 April 2016 at 08:32, Suzuki K Poulose <Suzuki.Poulose@xxxxxxx> wrote:
On 22/04/16 18:14, Mathieu Poirier wrote:

+ spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (drvdata->reading) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ val = local_xchg(&drvdata->mode, mode);
+ /*
+ * In Perf mode there can be only one writer per sink. There
+ * is also no need to continue if the ETR is already operated
+ * from sysFS.
+ */
+ if (val != CS_MODE_DISABLED) {


Could val be CS_MODE_PERF ? In other words, should we be checking :
if (val == CS_MODE_SYSFS) instead ?

If we check for CS_MODE_SYSFS we also have to check for CS_MODE_PERF,
which is two checks rather than a single one with the current
solution.

I am confused now. The comment says, we want to check for sysfs mode and
don't continue in that case. So, we shouldn't be worried about PERF mode.

Suzuki