From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: linux-rockchip@lists.infradead.org Cc: linux-clk@vger.kernel.org, dianders@chromium.org, mturquette@baylibre.com, sboyd@codeaurora.org, Chris Zhong Subject: Re: [PATCH] clk: rockchip: only enter pll slow-mode directly before reboots on rk3288 Date: Mon, 21 Dec 2015 02:06:10 +0100 Message-ID: <2178082.zdAf6brHOY@diego> In-Reply-To: <1705995.CL2pqRBHZb@diego> References: <1705995.CL2pqRBHZb@diego> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" List-ID: Am Freitag, 18. Dezember 2015, 19:33:50 schrieb Heiko St=FCbner: > As commit 1d33929e2a2b ("clk: rockchip: switch PLLs to slow mode befo= re > reboot for rk3288") states, switching the PLLs to slow-mode is only > necessary when rebooting using the soft-reset done through the CRU. >=20 > The dwc2 controllers used create really big number of interrupts in > special constellations involving usb-hubs and their number is so high= , > it can even overwhelm the interrupt handler if the cpu-speed os to lo= w. >=20 > Right now the PLLs are put into slow-mode in a shutdown syscore_ops > callback which means it happens on all reboots (not only the soft-res= et > ones) and even on poweroff actions. >=20 > This can result in the system not powering off and getting stuck inst= ead, > so we should move the slow-mode change nearer to the actual reboot ac= tion. >=20 > For this we introduce the possiblity to also set a callback that gets= > called from the restart-handler directly prior to restarting the syst= em > and move the shutdown-callback to this new option. >=20 > With this the slow-mode switch is done only on the necessary reboots > and also has a smaller possibility of causing artifacts. >=20 > Fixes: 1d33929e2a2b ("clk: rockchip: switch PLLs to slow mode before = reboot > for rk3288") Signed-off-by: Heiko Stuebner applied to my clk branch for 4.5