Messages in this thread | | | From | Andy Duan <> | Subject | RE: [EXT] Re: [PATCH net v2] net: fec: add a check for CONFIG_PM to avoid clock count mis-match | Date | Wed, 13 Nov 2019 01:50:20 +0000 |
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From: David Miller <davem@davemloft.net> Sent: Wednesday, November 13, 2019 3:13 AM > From: Chuhong Yuan <hslester96@gmail.com> > Date: Tue, 12 Nov 2019 19:28:30 +0800 > > > If CONFIG_PM is enabled, runtime pm will work and call runtime_suspend > > automatically to disable clks. > > Therefore, remove only needs to disable clks when CONFIG_PM is disabled. > > Add this check to avoid clock count mis-match caused by double-disable. > > > > Fixes: c43eab3eddb4 ("net: fec: add missed clk_disable_unprepare in > > remove") > > Signed-off-by: Chuhong Yuan <hslester96@gmail.com> > > I don't understand this at all. > > The clk disables here match the unconditional clk enables in the probe > function. > > And that is how this is supposed to work, probe enables match remove > disables. And suspend disables match resume enables. > > Why isn't the probe enable taking the correct count, which the remove > function must match with an appropriate disable? There is no CONFIG_PM > guarding the probe time clk enables.
Current driver runtime pm callback enable/disable clk_ipg/clk_ahb two clks. CONFIG_PM is a optional config, if CONFIG_PM is disabled, runtime callbacks will Not be called. The driver enable clk_ipg/clk_ahb two clks during probe, and depends runtime suspend to disable the two clks if CONFIG_PM is enabled.
In driver remove() also need to disable the two clks if CONIFG_PM is disabled. So the patch c43eab3eddb4 ("net: fec: add missed clk_disable_unprepare in emove") target the fixes if CONFIG_PM is not enabled, but the patch ignore to check the CONFIG_PM that make clock count mismatch in CONFIG_PM enabled case.
Andy
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