From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: rjw@rjwysocki.net, mroos@linux.ee, viresh.kumar@linaro.org
Cc: cpufreq@vger.kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, srivatsa.bhat@linux.vnet.ibm.com
Subject: [PATCH 3/3] cpufreq, powernow-k7: Fix double invocation of cpufreq_freq_transition_begin/end
Date: Fri, 25 Apr 2014 13:48:35 +0530 [thread overview]
Message-ID: <20140425081830.10258.10979.stgit@srivatsabhat.in.ibm.com> (raw)
In-Reply-To: <20140425081728.10258.63980.stgit@srivatsabhat.in.ibm.com>
During frequency transitions, the cpufreq core takes the responsibility of
invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end()
for those cpufreq drivers that define the ->target_index callback but don't
set the ASYNC_NOTIFICATION flag.
The powernow-k7 cpufreq driver falls under this category, but this driver was
invoking the _begin() and _end() APIs itself around frequency transitions,
which led to double invocation of the _begin() API. The _begin API makes
contending callers wait until the previous invocation is complete. Hence,
the powernow-k7 driver ended up waiting on itself, leading to system hangs
during boot.
Fix this by removing the calls to the _begin() and _end() APIs from the
powernow-k7 driver, since they rightly belong to the cpufreq core.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---
drivers/cpufreq/powernow-k7.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/cpufreq/powernow-k7.c b/drivers/cpufreq/powernow-k7.c
index f911645..e61e224 100644
--- a/drivers/cpufreq/powernow-k7.c
+++ b/drivers/cpufreq/powernow-k7.c
@@ -269,8 +269,6 @@ static int powernow_target(struct cpufreq_policy *policy, unsigned int index)
freqs.new = powernow_table[index].frequency;
- cpufreq_freq_transition_begin(policy, &freqs);
-
/* Now do the magic poking into the MSRs. */
if (have_a0 == 1) /* A0 errata 5 */
@@ -290,8 +288,6 @@ static int powernow_target(struct cpufreq_policy *policy, unsigned int index)
if (have_a0 == 1)
local_irq_enable();
- cpufreq_freq_transition_end(policy, &freqs, 0);
-
return 0;
}
next prev parent reply other threads:[~2014-04-25 8:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-25 8:17 [PATCH 0/3] Cpufreq frequency serialization fixes Srivatsa S. Bhat
2014-04-25 8:18 ` [PATCH 1/3] cpufreq, longhaul: Fix double invocation of cpufreq_freq_transition_begin/end Srivatsa S. Bhat
2014-04-25 8:37 ` Viresh Kumar
2014-04-25 8:39 ` Srivatsa S. Bhat
2014-04-25 8:18 ` [PATCH 2/3] cpufreq, powernow-k6: " Srivatsa S. Bhat
2014-04-25 8:28 ` Viresh Kumar
2014-04-25 8:42 ` Srivatsa S. Bhat
2014-04-25 8:18 ` Srivatsa S. Bhat [this message]
2014-04-25 8:24 ` [PATCH 3/3] cpufreq, powernow-k7: " Viresh Kumar
2014-04-25 17:29 ` [PATCH 0/3] Cpufreq frequency serialization fixes Meelis Roos
2014-04-28 18:47 ` Srivatsa S. Bhat
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140425081830.10258.10979.stgit@srivatsabhat.in.ibm.com \
--to=srivatsa.bhat@linux.vnet.ibm.com \
--cc=cpufreq@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mroos@linux.ee \
--cc=rjw@rjwysocki.net \
--cc=viresh.kumar@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).