From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755912Ab2JINcm (ORCPT ); Tue, 9 Oct 2012 09:32:42 -0400 Received: from co1ehsobe005.messaging.microsoft.com ([216.32.180.188]:30495 "EHLO co1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755665Ab2JINcg (ORCPT ); Tue, 9 Oct 2012 09:32:36 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: 0 X-BigFish: VS0(zzzz1202h1d1ah1d2ahzz8275bhz2dh2a8h668h839hd24he5bhf0ah107ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1155h) From: Fabio Estevam To: CC: , , , , Fabio Estevam Subject: [PATCH v3] video: imxfb: Do not crash on reboot Date: Tue, 9 Oct 2012 10:32:21 -0300 Message-ID: <1349789541-5159-1-git-send-email-fabio.estevam@freescale.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Content-Type: text/plain X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Issuing a "reboot" command after the LCD times out causes the following warnings: Requesting system reboot ------------[ cut here ]------------ WARNING: at drivers/clk/clk.c:471 clk_disable+0x24/0x50() Modules linked in: [] (unwind_backtrace+0x0/0xf4) from [] (warn_slowpath_common+0x48/0x60) [] (warn_slowpath_common+0x48/0x60) from [] (warn_slowpath_null+0x1c/0x24) [] (warn_slowpath_null+0x1c/0x24) from [] (clk_disable+0x24/0x50) [] (clk_disable+0x24/0x50) from [] (imxfb_disable_controller+0x48/0x7c) [] (imxfb_disable_controller+0x48/0x7c) from [] (platform_drv_shutdown+0x18/0x1c) [] (platform_drv_shutdown+0x18/0x1c) from [] (device_shutdown+0x48/0x14c) [] (device_shutdown+0x48/0x14c) from [] (kernel_restart_prepare+0x2c/0x3c) [] (kernel_restart_prepare+0x2c/0x3c) from [] (kernel_restart+0xc/0x48) [] (kernel_restart+0xc/0x48) from [] (sys_reboot+0xc0/0x1bc) [] (sys_reboot+0xc0/0x1bc) from [] (ret_fast_syscall+0x0/0x2c) ---[ end trace da6b502ca79c854f ]--- ------------[ cut here ]------------ WARNING: at drivers/clk/clk.c:380 clk_unprepare+0x1c/0x2c() Modules linked in: [] (unwind_backtrace+0x0/0xf4) from [] (warn_slowpath_common+0x48/0x60) [] (warn_slowpath_common+0x48/0x60) from [] (warn_slowpath_null+0x1c/0x24) [] (warn_slowpath_null+0x1c/0x24) from [] (clk_unprepare+0x1c/0x2c) [] (clk_unprepare+0x1c/0x2c) from [] (imxfb_disable_controller+0x50/0x7c) [] (imxfb_disable_controller+0x50/0x7c) from [] (platform_drv_shutdown+0x18/0x1c) [] (platform_drv_shutdown+0x18/0x1c) from [] (device_shutdown+0x48/0x14c) [] (device_shutdown+0x48/0x14c) from [] (kernel_restart_prepare+0x2c/0x3c) [] (kernel_restart_prepare+0x2c/0x3c) from [] (kernel_restart+0xc/0x48) [] (kernel_restart+0xc/0x48) from [] (sys_reboot+0xc0/0x1bc) [] (sys_reboot+0xc0/0x1bc) from [] (ret_fast_syscall+0x0/0x2c) ---[ end trace da6b502ca79c8550 ]--- ------------[ cut here ]------------ This happens because "reboot" triggers imxfb_shutdown(), which calls imxfb_disable_controller with the clocks already disabled. To prevent this, add a clock enabled status so that we can check if the clocks are enabled before disabling them. Signed-off-by: Fabio Estevam --- Changes since v2: - Use a better naming for the clk enabled variable - Return immediately in imxfb_enable_controller/imxfb_disable_controller if the the clocks are already enabled/disabled. Changes since v1: - Protect the whole function instead of only the clocks drivers/video/imxfb.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/video/imxfb.c b/drivers/video/imxfb.c index cf2688d..e0d770f 100644 --- a/drivers/video/imxfb.c +++ b/drivers/video/imxfb.c @@ -134,6 +134,7 @@ struct imxfb_info { struct clk *clk_ipg; struct clk *clk_ahb; struct clk *clk_per; + int clks_enabled; /* * These are the addresses we mapped @@ -513,6 +514,9 @@ static void imxfb_exit_backlight(struct imxfb_info *fbi) static void imxfb_enable_controller(struct imxfb_info *fbi) { + if (fbi->clks_enabled) + return; + pr_debug("Enabling LCD controller\n"); writel(fbi->screen_dma, fbi->regs + LCDC_SSA); @@ -533,6 +537,7 @@ static void imxfb_enable_controller(struct imxfb_info *fbi) clk_prepare_enable(fbi->clk_ipg); clk_prepare_enable(fbi->clk_ahb); clk_prepare_enable(fbi->clk_per); + fbi->clks_enabled = 1; if (fbi->backlight_power) fbi->backlight_power(1); @@ -542,6 +547,9 @@ static void imxfb_enable_controller(struct imxfb_info *fbi) static void imxfb_disable_controller(struct imxfb_info *fbi) { + if (!fbi->clks_enabled) + return; + pr_debug("Disabling LCD controller\n"); if (fbi->backlight_power) @@ -552,6 +560,7 @@ static void imxfb_disable_controller(struct imxfb_info *fbi) clk_disable_unprepare(fbi->clk_per); clk_disable_unprepare(fbi->clk_ipg); clk_disable_unprepare(fbi->clk_ahb); + fbi->clks_enabled = 0; writel(0, fbi->regs + LCDC_RMCR); } -- 1.7.9.5