From: Stanley Chu <stanley.chu@mediatek.com>
To: Can Guo <cang@codeaurora.org>
Cc: <asutoshd@codeaurora.org>, <nguyenb@codeaurora.org>,
<hongwus@codeaurora.org>, <linux-scsi@vger.kernel.org>,
<kernel-team@android.com>, Alim Akhtar <alim.akhtar@samsung.com>,
Avri Altman <avri.altman@wdc.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Bean Huo <beanhuo@micron.com>,
"Satya Tangirala" <satyat@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v11 1/3] scsi: ufs: Protect some contexts from unexpected clock scaling
Date: Wed, 20 Jan 2021 21:14:32 +0800 [thread overview]
Message-ID: <1611148472.1261.6.camel@mtkswgap22> (raw)
In-Reply-To: <1611137065-14266-2-git-send-email-cang@codeaurora.org>
On Wed, 2021-01-20 at 02:04 -0800, Can Guo wrote:
> In contexts like suspend, shutdown and error handling, we need to suspend
> devfreq to make sure these contexts won't be disturbed by clock scaling.
> However, suspending devfreq is not enough since users can still trigger a
> clock scaling by manipulating the devfreq sysfs nodes like min/max_freq and
> governor even after devfreq is suspended. Moreover, mere suspending devfreq
> cannot synchroinze a clock scaling which has already been invoked through
> these sysfs nodes. Add one more flag in struct clk_scaling and wrap the
> entire func ufshcd_devfreq_scale() with the clk_scaling_lock, so that we
> can use this flag and clk_scaling_lock to control and synchronize clock
> scaling invoked through devfreq sysfs nodes.
>
> Signed-off-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
next prev parent reply other threads:[~2021-01-20 13:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1611137065-14266-1-git-send-email-cang@codeaurora.org>
2021-01-20 10:04 ` [PATCH v11 1/3] scsi: ufs: Protect some contexts from unexpected clock scaling Can Guo
2021-01-20 13:14 ` Stanley Chu [this message]
2021-01-20 10:04 ` [PATCH v11 2/3] scsi: ufs: Refactor ufshcd_init/exit_clk_scaling/gating() Can Guo
2021-01-20 10:04 ` [PATCH v11 3/3] scsi: ufs: Revert "Make sure clk scaling happens only when HBA is runtime ACTIVE" Can Guo
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