linux-kernel - Question about suspend/resume clock handling in dwc3-of-simple.c

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160912185629.GA25929@roeck-us.net>
Date:   Mon, 12 Sep 2016 11:56:29 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Felipe Balbi <balbi@...nel.org>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Question about suspend/resume clock handling in dwc3-of-simple.c

Hi folks,

In dwc3-of-simple.c:dwc3_of_simple_remove(), I see the following code.

	for (i = 0; i < simple->num_clocks; i++) {
                clk_unprepare(simple->clks[i]);
		clk_put(simple->clks[i]);
	}

What I don't understand is why clk_unprepare() is called instead
of clk_disable_unprepare(). Someone told me that it was due to
dwc3_of_simple_runtime_suspend(), which would call clk_disable().

That doesn't really make sense to me, since after all CONFIG_PM
can be disabled.

Should it be clk_disable_unprepare(), or maybe something like the
following

	if (!pm_runtime_status_suspended(dev))
		clk_disable_unprepare();
	else
		clk_unprepare();

or am I missing something ?

Thanks,
Guenter