Stanley Chu 4351cf25cb scsi: ufs: Fix possible power drain during system suspend
commit 1d53864c3617f5235f891ca0fbe9347c4cd35d46 upstream.

Currently if device needs to do flush or BKOP operations, the device VCC
power is kept during runtime-suspend period.

However, if system suspend is happening while device is runtime-suspended,
such power may not be disabled successfully.

The reasons may be,

1. If current PM level is the same as SPM level, device will keep
   runtime-suspended by ufshcd_system_suspend().

2. Flush recheck work may not be scheduled successfully during system
   suspend period. If it can wake up the system, this is also not the
   intention of the recheck work.

To fix this issue, simply runtime-resume the device if the flush is allowed
during runtime suspend period. Flush capability will be disabled while
leaving runtime suspend, and also not be allowed in system suspend period.

Link: https://lore.kernel.org/r/20201222072905.32221-2-stanley.chu@mediatek.com
Fixes: 51dd905bd2f6 ("scsi: ufs: Fix WriteBooster flush during runtime suspend")
Reviewed-by: Chaotian Jing <chaotian.jing@mediatek.com>
Reviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-19 18:27:31 +01:00
2021-01-19 18:27:28 +01:00
2021-01-12 20:18:22 +01:00
2020-10-17 11:18:18 -07:00
2021-01-17 14:17:06 +01:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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