From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Fries <david@fries.net>,
Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Subject: [PATCH 18/30] W1: ds1wm.c msleep for reset
Date: Fri, 11 Jul 2008 17:51:33 +0400 [thread overview]
Message-ID: <1215784306270-git-send-email-johnpol@2ka.mipt.ru> (raw)
In-Reply-To: <12157843054074-git-send-email-johnpol@2ka.mipt.ru>
Like the previous w1_io.c reset coments and msleep patch, I don't have
the hardware to verify the change, but I think it is safe. It also
helps to see a comment like this in the code.
"We'll wait a bit longer just to be sure."
If they are going to calculate delaying 324.9us, but actually delay
500us, why not just give up the CPU and sleep? This is designed for a
battery powered ARM system, avoiding busywaiting has to be good for
battery life.
I sent a request for testers March 7, 2008 to the Linux kernel mailing
list and two developers who have patches for ds1wm.c, but I didn't get
any respons.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
---
drivers/w1/masters/ds1wm.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
index ea894bf..29e144f 100644
--- a/drivers/w1/masters/ds1wm.c
+++ b/drivers/w1/masters/ds1wm.c
@@ -160,8 +160,10 @@ static int ds1wm_reset(struct ds1wm_data *ds1wm_data)
* 625 us - 60 us - 240 us - 100 ns = 324.9 us
*
* We'll wait a bit longer just to be sure.
+ * Was udelay(500), but if it is going to busywait the cpu that long,
+ * might as well come back later.
*/
- udelay(500);
+ msleep(1);
ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD |
--
1.4.4.4
next prev parent reply other threads:[~2008-07-11 13:52 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-11 13:51 w1 updates Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 1/30] W1: fix deadlocks and remove w1_control_thread Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 2/30] W1: abort search early on on exit Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 3/30] W1: don't delay search start Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 4/30] W1: w1_process, block or sleep Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 5/30] W1: feature, enable hardware strong pullup Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 6/30] W1: feature, w1_therm.c use strong pullup and documentation Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 7/30] W1: be able to manually add and remove slaves Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 8/30] W1: recode w1_slave_found logic Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 9/30] W1: new module parameter search_count Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 10/30] W1: Document add, remove, search_count, and pullup Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 11/30] W1: w1_slave_read_id read bug, use device_attribute Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 12/30] W1: w1_therm fix user buffer overflow and cat Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 13/30] W1: w1_family, remove unused variable need_exit Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 14/30] W1: w1_therm consistent mutex access code cleanup Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 15/30] W1: w1_int.c use first available master number Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 16/30] W1: w1.c s/printk/dev_dbg/ Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 17/30] W1: w1_io.c reset comments and msleep Evgeniy Polyakov
2008-07-11 13:51 ` Evgeniy Polyakov [this message]
2008-07-11 13:51 ` [PATCH 19/30] W1: ds2490.c correct print message Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 20/30] W1: ds2490.c add support for strong pullup Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 21/30] W1: ds2490.c ds_write_bit, grouping error, disable readback Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 22/30] W1: ds2490.c disable bit read and write Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 23/30] W1: ds2490.c simplify and fix ds_touch_bit Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 24/30] W1: ds2490.c ds_dump_status rework Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 25/30] W1: ds2490.c ds_reset remove ds_wait_status Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 26/30] W1: ds2490.c reset ds2490 in init Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 27/30] W1: ds2490.c magic number work Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 28/30] W1: ds2490.c ds_write_block remove extra ds_wait_status Evgeniy Polyakov
2008-07-11 13:51 ` [PATCH 29/30] W1: Documentation/w1/masters/ds2490 update Evgeniy Polyakov
2008-07-14 20:40 ` Randy Dunlap
2008-07-15 2:16 ` David Fries
2008-07-17 21:52 ` Randy Dunlap
2008-07-15 2:17 ` David Fries
2008-07-11 13:51 ` [PATCH 30/30] W1: ds2490.c optimize ds_set_pullup Evgeniy Polyakov
-- strict thread matches above, loose matches on Subject: below --
2008-07-29 2:04 [PATCH 0/30] W1: w1 core fixes, ds2490 updates, strong pullup David Fries
2008-07-29 2:24 ` [PATCH 18/30] W1: ds1wm.c msleep for reset David Fries
2008-07-29 23:13 ` [PATCH 0/30] W1: w1 core fixes, ds2490 updates, strong pullup Andrew Morton
2008-07-31 2:49 ` [PATCH 18/30] W1: ds1wm.c msleep for reset David Fries
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