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Message-ID: <17495106.TRDjcDkMKC@diego> Date: Fri, 12 Apr 2019 12:06:45 +0200 From: Heiko Stübner <heiko@...ech.de> To: Douglas Anderson <dianders@...omium.org> Cc: Elaine Zhang <zhangqing@...k-chips.com>, dbasehore@...omium.org, amstan@...omium.org, linux-rockchip@...ts.infradead.org, briannorris@...omium.org, mka@...omium.org, ryandcase@...omium.org, Chris Zhong <zyw@...k-chips.com>, Michael Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org Subject: Re: [PATCH 1/5] clk: rockchip: Turn on "aclk_dmac1" for suspend Am Freitag, 12. April 2019, 01:21:53 CEST schrieb Douglas Anderson: > Experimentally it can be seen that going into deep sleep (specifically > setting PMU_CLR_DMA and PMU_CLR_BUS in RK3288_PMU_PWRMODE_CON1) > appears to fail unless "aclk_dmac1" is on. The failure is that the > system never signals that it made it into suspend on the GLOBAL_PWROFF > pin and it just hangs. > > NOTE that it's confirmed that it's the actual suspend that fails, not > one of the earlier calls to read/write registers. Specifically if you > comment out the "PMU_GLOBAL_INT_DISABLE" setting in > rk3288_slp_mode_set() and then comment out the "cpu_do_idle()" call in > rockchip_lpmode_enter() then you can exercise the whole suspend path > without any crashing. > > This is currently not a problem with suspend upstream because there is > no current way to exercise the deep suspend code. However, anyone > trying to make it work will run into this issue. > > This was not a problem on shipping rk3288-based Chromebooks because > those devices all ran on an old kernel based on 3.14. On that kernel > "aclk_dmac1" appears to be left on all the time. > > There are several ways to skin this problem. > > A) We could add "aclk_dmac1" to the list of critical clocks and that > apperas to work, but presumably that wastes power. > > B) We could keep a list of "struct clk" objects to enable at suspend > time in clk-rk3288.c and use the standard clock APIs. > > C) We could make the rk3288-pmu driver keep a list of clocks to enable > at suspend time. Presumably this would require a dts and bindings > change. > > D) We could just whack the clock on in the existing syscore suspend > function where we whack a bunch of other clocks. This is particularly > easy because we know for sure that the clock's only parent > ("aclk_cpu") is a critical clock so we don't need to do anything more > than ungate it. > > In this case I have chosen D) because it seemed like the least work, > but any of the other options would presumably also work fine. > > Signed-off-by: Douglas Anderson <dianders@...omium.org> applied for 5.2 with Elaine's rb Thanks Heiko
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