Hi Mark,
> > ds1374_set_tlet triggers many i2c transfers, which may delay or sleep
> > depending on the underlying i2c implementation, and definitely will
> > take some time (at least 224 I2C clock cycles if I'm counting properly,
> > that is 14 ms at 16 kHz.)
> >
> > So I came to the conclusion that it wouldn't be fair to other users if
> > ds1374 was using the shared workqueue. Now, I really don't know for
> > sure, so I'll let workqueue experts decide what should be done here.
>
> Hmm, you raise a good point, Jean. I just talked to Randy and we agreed
> to agree with you. :) Randy will make a patch for the ds1374 and I'll
> rework the patches for the m41t00. Stay tuned...
Well I already have a patch for ds1374. This is basically a mix between
Randy's and my original patch: I've kept the dedicated workqueue as my
patch had, but preserved the in_interrupt() call as in Randy's. Here's
the result:
* * * * *
A tasklet is not suitable for what the ds1374 driver does: neither sleeping
nor mutex operations are allowed in tasklets, and ds1374_set_tlet may do
both.
We can use a workqueue instead, where both sleeping and mutex operations
are allowed.
Signed-off-by: Jean Delvare <[email protected]>
---
drivers/i2c/chips/ds1374.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- linux-2.6.16-git.orig/drivers/i2c/chips/ds1374.c 2006-03-27 18:25:17.000000000 +0200
+++ linux-2.6.16-git/drivers/i2c/chips/ds1374.c 2006-03-27 18:59:05.000000000 +0200
@@ -27,6 +27,7 @@
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/mutex.h>
+#include <linux/workqueue.h>
#define DS1374_REG_TOD0 0x00
#define DS1374_REG_TOD1 0x01
@@ -139,7 +140,7 @@
return t1;
}
-static void ds1374_set_tlet(ulong arg)
+static void ds1374_set_work(void *arg)
{
ulong t1, t2;
int limit = 10; /* arbitrary retry limit */
@@ -168,17 +169,18 @@
static ulong new_time;
-static DECLARE_TASKLET_DISABLED(ds1374_tasklet, ds1374_set_tlet,
- (ulong) & new_time);
+static struct workqueue_struct *ds1374_workqueue;
+
+static DECLARE_WORK(ds1374_work, ds1374_set_work, &new_time);
int ds1374_set_rtc_time(ulong nowtime)
{
new_time = nowtime;
if (in_interrupt())
- tasklet_schedule(&ds1374_tasklet);
+ queue_work(ds1374_workqueue, &ds1374_work);
else
- ds1374_set_tlet((ulong) & new_time);
+ ds1374_set_work(&new_time);
return 0;
}
@@ -204,6 +206,8 @@
client->adapter = adap;
client->driver = &ds1374_driver;
+ ds1374_workqueue = create_singlethread_workqueue("ds1374");
+
if ((rc = i2c_attach_client(client)) != 0) {
kfree(client);
return rc;
@@ -227,7 +231,7 @@
if ((rc = i2c_detach_client(client)) == 0) {
kfree(i2c_get_clientdata(client));
- tasklet_kill(&ds1374_tasklet);
+ destroy_workqueue(ds1374_workqueue);
}
return rc;
}
* * * * *
If it's OK, then Randy can just sign it off and I'll push it to Greg
quickly. If it's not OK for some reason, I'll just wait for a new patch
from Randy.
Thanks,
--
Jean Delvare
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