Re: [PATCH] video/omap2. dispc_mgr_enable needs runtime PM

[NeilBrown <neilb@suse.de>]

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On Wed, 04 Jan 2012 09:50:56 +0200 Tomi Valkeinen <tomi.valkeinen@ti.com>
wrote:

> (dropping the Tony and Kevin, as they're probably not interested in
> this)

Thanks.... takes a while to figure who cares about what :-)

> 
> On Fri, 2011-12-30 at 12:37 +1100, NeilBrown wrote:
> > 
> > When dispc_mgr_enable is called during shutdown the device might
> > be asleep, which causes problems.  So ensure it is awake.
> 
> How does this problem happen? dispc_mgr_enable(channel, false) shouldn't
> be called if the device is asleep, and thus dispc_mgr_enable() shouldn't
> use dispc_runtime_get.
> 
>  Tomi
> 

The stack trace shows:

[  101.764556] [<c0205b3c>] (dispc_mgr_enable+0x40/0x2e0) from [<c020c10c>] (dss_mgr_disable+0x14/0x20)
[  101.774078] [<c020c10c>] (dss_mgr_disable+0x14/0x20) from [<c020e500>] (omapdss_dpi_display_disable+0x1c/0x88)
[  101.784484] [<c020e500>] (omapdss_dpi_display_disable+0x1c/0x88) from [<c021efa4>] (td028ttec1_panel_suspend+0x1c/0x88)
[  101.795684] [<c021efa4>] (td028ttec1_panel_suspend+0x1c/0x88) from [<c021f03c>] (td028ttec1_panel_disable+0x2c/0x50)
[  101.806640] [<c021f03c>] (td028ttec1_panel_disable+0x2c/0x50) from [<c020ab6c>] (dss_disable_device+0x20/0x2c)
[  101.817047] [<c020ab6c>] (dss_disable_device+0x20/0x2c) from [<c024ad08>] (bus_for_each_dev+0x4c/0x8c)
[  101.826751] [<c024ad08>] (bus_for_each_dev+0x4c/0x8c) from [<c024ca0c>] (platform_drv_shutdown+0x1c/0x24)
[  101.836700] [<c024ca0c>] (platform_drv_shutdown+0x1c/0x24) from [<c0248164>] (device_shutdown+0xcc/0x10c)
[  101.846679] [<c0248164>] (device_shutdown+0xcc/0x10c) from [<c004c134>] (kernel_power_off+0x10/0x4c)
[  101.856170] [<c004c134>] (kernel_power_off+0x10/0x4c) from [<c004c420>] (sys_reboot+0x124/0x1e0)
[  101.865325] [<c004c420>] (sys_reboot+0x124/0x1e0) from [<c000e9c0>] (ret_fast_syscall+0x0/0x3c)


td028ttec1_panel_* are in a non-mainline driver that could well be buggy.
.....
yep, that looks likely.  The 'disable' routines of other panels only call
omapdss_dpi_display_disable() if (dssdev->state == OMAP_DSS_DISPLAY_ACTIVE).
This panel calls it unconditionally.  I guess that is the real bug? (and
putting an appropriate test in fixes it).

Thanks for your help.

(If/when I get this td028ttec driver cleaned up, would you be the one I send
it to?)

Thanks,
NeilBrown

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