From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Vinayak Holikatti <vinholikatti@gmail.com>,
"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Chanwoo Choi <cw00.choi@samsung.com>,
linux-scsi@vger.kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Vivek Gautam <vivek.gautam@codeaurora.org>
Subject: [PATCH v2 0/2] Fix UFS and devfreq interaction
Date: Fri, 4 May 2018 15:44:25 -0700 [thread overview]
Message-ID: <20180504224427.32606-1-bjorn.andersson@linaro.org> (raw)
With the introduction of f1d981eaecf8 ("PM / devfreq: Use the available min/max
frequency") the UFS host controller driver (UFSHCD) stopped probing for
platforms that supports frequency scaling, e.g. all modern Qualcomm platforms.
The cause of this was UFSHCD's reliance of not registering any frequencies and
then being called by devfreq to switch between the frequencies 0 and UINT_MAX.
The devfreq code implies that the client is able to pass the frequency table,
instead of relying on opp tables, but as concluded after v1 this is not
compliant with devfreq cooling, which will enable and disable opp entries in
order to limit the valid frequencies. So instead the UFSHCD driver is modified
to read the freq-table and register the first clock's two rates as the two
available opp levels.
This follows the first patch which facilitates the implementation of this in a
clean fashion, and removes the kernel panic which previously happened when
devfreq initialization failed.
With this UFS is once again functional on the db820c, and is needed to get UFS
working on SDM845 (both tested).
Bjorn Andersson (2):
scsi: ufs: Extract devfreq registration
scsi: ufs: Use freq table with devfreq
drivers/scsi/ufs/ufshcd.c | 76 +++++++++++++++++++++++++++++++--------
1 file changed, 61 insertions(+), 15 deletions(-)
--
2.17.0
next reply other threads:[~2018-05-04 22:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-04 22:44 Bjorn Andersson [this message]
2018-05-04 22:44 ` [PATCH v2 1/2] scsi: ufs: Extract devfreq registration Bjorn Andersson
2018-05-08 1:59 ` Chanwoo Choi
2018-05-04 22:44 ` [PATCH v2 2/2] scsi: ufs: Use freq table with devfreq Bjorn Andersson
2018-05-08 2:51 ` Chanwoo Choi
2018-05-16 21:20 ` Subhash Jadavani
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=20180504224427.32606-1-bjorn.andersson@linaro.org \
--to=bjorn.andersson@linaro.org \
--cc=cw00.choi@samsung.com \
--cc=jejb@linux.vnet.ibm.com \
--cc=kyungmin.park@samsung.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=myungjoo.ham@samsung.com \
--cc=vinholikatti@gmail.com \
--cc=vivek.gautam@codeaurora.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).