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Message-ID: <1349703336-8105-1-git-send-email-fabio.estevam@freescale.com>
Date: Mon, 8 Oct 2012 10:35:36 -0300
From: Fabio Estevam <fabio.estevam@...escale.com>
To: <kernel@...gutronix.de>
CC: <FlorianSchandinat@....de>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
Fabio Estevam <fabio.estevam@...escale.com>
Subject: [PATCH] video: imxfb: Do not crash on reboot
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:
[<c001ad90>] (unwind_backtrace+0x0/0xf4) from [<c0025aac>] (warn_slowpath_common+0x48/0x60)
[<c0025aac>] (warn_slowpath_common+0x48/0x60) from [<c0025ae0>] (warn_slowpath_null+0x1c/0x24)
[<c0025ae0>] (warn_slowpath_null+0x1c/0x24) from [<c03960a0>] (clk_disable+0x24/0x50)
[<c03960a0>] (clk_disable+0x24/0x50) from [<c02695a0>] (imxfb_disable_controller+0x48/0x7c)
[<c02695a0>] (imxfb_disable_controller+0x48/0x7c) from [<c029d838>] (platform_drv_shutdown+0x18/0x1c)
[<c029d838>] (platform_drv_shutdown+0x18/0x1c) from [<c02990fc>] (device_shutdown+0x48/0x14c)
[<c02990fc>] (device_shutdown+0x48/0x14c) from [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c)
[<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) from [<c003d0e4>] (kernel_restart+0xc/0x48)
[<c003d0e4>] (kernel_restart+0xc/0x48) from [<c003d1e8>] (sys_reboot+0xc0/0x1bc)
[<c003d1e8>] (sys_reboot+0xc0/0x1bc) from [<c0014ca0>] (ret_fast_syscall+0x0/0x2c)
---[ end trace da6b502ca79c854f ]---
------------[ cut here ]------------
WARNING: at drivers/clk/clk.c:380 clk_unprepare+0x1c/0x2c()
Modules linked in:
[<c001ad90>] (unwind_backtrace+0x0/0xf4) from [<c0025aac>] (warn_slowpath_common+0x48/0x60)
[<c0025aac>] (warn_slowpath_common+0x48/0x60) from [<c0025ae0>] (warn_slowpath_null+0x1c/0x24)
[<c0025ae0>] (warn_slowpath_null+0x1c/0x24) from [<c0396338>] (clk_unprepare+0x1c/0x2c)
[<c0396338>] (clk_unprepare+0x1c/0x2c) from [<c02695a8>] (imxfb_disable_controller+0x50/0x7c)
[<c02695a8>] (imxfb_disable_controller+0x50/0x7c) from [<c029d838>] (platform_drv_shutdown+0x18/0x1c)
[<c029d838>] (platform_drv_shutdown+0x18/0x1c) from [<c02990fc>] (device_shutdown+0x48/0x14c)
[<c02990fc>] (device_shutdown+0x48/0x14c) from [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c)
[<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) from [<c003d0e4>] (kernel_restart+0xc/0x48)
[<c003d0e4>] (kernel_restart+0xc/0x48) from [<c003d1e8>] (sys_reboot+0xc0/0x1bc)
[<c003d1e8>] (sys_reboot+0xc0/0x1bc) from [<c0014ca0>] (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 <fabio.estevam@...escale.com>
---
drivers/video/imxfb.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/video/imxfb.c b/drivers/video/imxfb.c
index f3363b2..6acf98a 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 enabled;
/*
* These are the addresses we mapped
@@ -530,9 +531,12 @@ static void imxfb_enable_controller(struct imxfb_info *fbi)
*/
writel(RMCR_LCDC_EN_MX1, fbi->regs + LCDC_RMCR);
- clk_prepare_enable(fbi->clk_ipg);
- clk_prepare_enable(fbi->clk_ahb);
- clk_prepare_enable(fbi->clk_per);
+ if (!fbi->enabled) {
+ clk_prepare_enable(fbi->clk_ipg);
+ clk_prepare_enable(fbi->clk_ahb);
+ clk_prepare_enable(fbi->clk_per);
+ fbi->enabled = 1;
+ }
if (fbi->backlight_power)
fbi->backlight_power(1);
@@ -551,9 +555,12 @@ static void imxfb_disable_controller(struct imxfb_info *fbi)
writel(0, fbi->regs + LCDC_RMCR);
- clk_disable_unprepare(fbi->clk_per);
- clk_disable_unprepare(fbi->clk_ipg);
- clk_disable_unprepare(fbi->clk_ahb);
+ if (fbi->enabled) {
+ clk_disable_unprepare(fbi->clk_per);
+ clk_disable_unprepare(fbi->clk_ipg);
+ clk_disable_unprepare(fbi->clk_ahb);
+ fbi->enabled = 0;
+ }
}
static int imxfb_blank(int blank, struct fb_info *info)
--
1.7.9.5
--
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