[PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Bhupesh Sharma]

As the V4L2 based UVC webcam gadget (g_webcam) expects the
'videodev' to present when the 'webcam_bind' routine is called,
so 'videodev' should be available as early as possible.

Now, when 'g_webcam' is built as a module (i.e. not a part of
kernel) the late availability of 'videodev' is OK, but if
'g_webcam' is built statically as a part of the kernel,
the kernel crashes (a sample crash dump using Designware 2.0 UDC
is provided below).

To solve the same, this patch makes 'videodev_init' as a subsys initcall.

Kernel Crash Dump:
------------------

designware_udc designware_udc: Device Synopsys UDC probed csr 90810000: plug 90812000
g_webcam gadget: uvc_function_bind
Unable to handle kernel NULL pointer dereference at virtual address 000000e4
pgd = 80004000
[000000e4] *pgd=00000000
Internal error: Oops: 5 [#1] SMP
Modules linked in:
CPU: 0    Not tainted  (3.3.0-rc3-13888-ge774c03-dirty #20)
PC is at do_raw_spin_lock+0x10/0x16c
LR is at _raw_spin_lock+0x10/0x14
pc : [<8019e344>]    lr : [<804095c0>]    psr: 60000013
sp : 8f839d20  ip : 8f839d50  fp : 8f839d4c
r10: 80760a94  r9 : 8042de98  r8 : 00000154
r7 : 80760e94  r6 : 805cfc10  r5 : 8fb6a008  r4 : 8fb6a008
r3 : 805dd0c8  r2 : 8f839d48  r1 : 805cfc08  r0 : 000000e0
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 10c5387d  Table: 0000404a  DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0x8f8382f0)
Stack: (0x8f839d20 to 0x8f83a000)
9d20: ffffffff ffffffff 8fb6a008 8fb6a008 805cfc10 80760e94 00000154 8042de98
9d40: 8f839d5c 8f839d50 804095c0 8019e340 8f839d7c 8f839d60 80222b28 804095bc
9d60: 8fb12b80 8fb6a008 8fb6a010 805cfc08 8f839dc4 8f839d80 80223db8 80222adc
9d80: 8f839dac 8f839d90 8022baa0 8019e2e8 8fb6a008 8075e7f4 8fb6a008 8fb6a008
9da0: 00000000 8fb6a008 80760e94 00000154 8042de98 80760a94 8f839ddc 8f839dc8
9dc0: 802242a8 80223d1c 8fb12b80 8fb6a000 8f839e1c 8f839de0 8030132c 80224298
9de0: 80223ce8 803f2ee8 00000001 804f7750 8f839e1c 8f824008 805cff20 8f824000
9e00: 8fb6a000 ffffffff 00000000 8f8d4880 8f839e4c 8f839e20 80562e3c 80301100
9e20: 00000000 8fb13140 8f824008 805cff20 8042aa68 8f824000 8042aa8c 805e4d40
9e40: 8f839e64 8f839e50 802d20c4 80562ba8 805d0058 805cff20 8f839e8c 8f839e68
9e60: 80563034 802d206c 8042aa8c 805cff20 8f8d4880 00000000 805cfc08 8fb12a40
9e80: 8f839e9c 8f839e90 805630c4 80562ec4 8f839ebc 8f839ea0 802d2364 805630b0
9ea0: 805cfeac 8f8d4880 805cfbe8 807605e8 8f839ed4 8f839ec0 80562b3c 802d22cc
9ec0: 80562ac4 8f8d4880 8f839f04 8f839ed8 802d0b40 80562ad0 8f839ef4 805cff90
9ee0: 805cff90 805cfb98 00000000 00000000 805cfbe8 805e4d40 8f839f3c 8f839f08
9f00: 802cd078 802d0a18 00000000 802d0a0c 00000000 8fb9ba00 802d0a0c 805cff90
9f20: 00000013 00000000 00000000 805e4d40 8f839f5c 8f839f40 802cf390 802ccff0
9f40: 00000003 00000003 804fb598 00000000 8f839f74 8f839f60 802d2554 802cf2a0
9f60: 8f838000 8057731c 8f839f84 8f839f78 80562b90 802d24d0 8f839fdc 8f839f88
9f80: 800085d4 80562b84 805af2ac 805af2ac 80562b78 00000000 00000013 00000000
9fa0: 00000000 00000000 8f839fc4 8f839fb8 80043dd0 8057706c 8057731c 8002875c
9fc0: 00000013 00000000 00000000 00000000 8f839ff4 8f839fe0 805468d4 800085a0
9fe0: 00000000 80546840 00000000 8f839ff8 8002875c 8054684c 51155555 55545555
Backtrace:
[<8019e334>] (do_raw_spin_lock+0x0/0x16c) from [<804095c0>] (_raw_spin_lock+0x10/0x14)
 r9:8042de98 r8:00000154 r7:80760e94 r6:805cfc10 r5:8fb6a008
r4:8fb6a008
[<804095b0>] (_raw_spin_lock+0x0/0x14) from [<80222b28>] (get_device_parent+0x58/0x1c0)
[<80222ad0>] (get_device_parent+0x0/0x1c0) from [<80223db8>] (device_add+0xa8/0x57c)
 r6:805cfc08 r5:8fb6a010 r4:8fb6a008 r3:8fb12b80
[<80223d10>] (device_add+0x0/0x57c) from [<802242a8>] (device_register+0x1c/0x20)
[<8022428c>] (device_register+0x0/0x20) from [<8030132c>] (__video_register_device+0x238/0x484)
 r4:8fb6a000 r3:8fb12b80
[<803010f4>] (__video_register_device+0x0/0x484) from [<80562e3c>] (uvc_function_bind+0x2a0/0x31c)
[<80562b9c>] (uvc_function_bind+0x0/0x31c) from [<802d20c4>] (usb_add_function+0x64/0x118)
[<802d2060>] (usb_add_function+0x0/0x118) from [<80563034>] (uvc_bind_config+0x17c/0x1ec)
 r5:805cff20 r4:805d0058
[<80562eb8>] (uvc_bind_config+0x0/0x1ec) from [<805630c4>] (webcam_config_bind+0x20/0x28)
 r8:8fb12a40 r7:805cfc08 r6:00000000 r5:8f8d4880 r4:805cff20
r3:8042aa8c
[<805630a4>] (webcam_config_bind+0x0/0x28) from [<802d2364>] (usb_add_config+0xa4/0x124)
[<802d22c0>] (usb_add_config+0x0/0x124) from [<80562b3c>] (webcam_bind+0x78/0xb4)
 r6:807605e8 r5:805cfbe8 r4:8f8d4880 r3:805cfeac
[<80562ac4>] (webcam_bind+0x0/0xb4) from [<802d0b40>] (composite_bind+0x134/0x308)
 r4:8f8d4880 r3:80562ac4
[<802d0a0c>] (composite_bind+0x0/0x308) from [<802cd078>] (dw_udc_start+0x94/0x2bc)
[<802ccfe4>] (dw_udc_start+0x0/0x2bc) from [<802cf390>] (usb_gadget_probe_driver+0xfc/0x180)
[<802cf294>] (usb_gadget_probe_driver+0x0/0x180) from [<802d2554>] (usb_composite_probe+0x90/0xb4)
 r6:00000000 r5:804fb598 r4:00000003 r3:00000003
[<802d24c4>] (usb_composite_probe+0x0/0xb4) from [<80562b90>] (webcam_init+0x18/0x24)
 r5:8057731c r4:8f838000
[<80562b78>] (webcam_init+0x0/0x24) from [<800085d4>] (do_one_initcall+0x40/0x184)
[<80008594>] (do_one_initcall+0x0/0x184) from [<805468d4>] (kernel_init+0x94/0x134)
[<80546840>] (kernel_init+0x0/0x134) from [<8002875c>] (do_exit+0x0/0x6f8)
 r5:80546840 r4:00000000
Code: e1a0c00d e92ddbf0 e24cb004 e24dd008 (e5902004)
---[ end trace 7ecca37f36fbdc06 ]---
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
---
 drivers/media/video/v4l2-dev.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
index 96e9615..041804b 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
 	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
 }
 
-module_init(videodev_init)
+subsys_initcall(videodev_init);
 module_exit(videodev_exit)
 
 MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
-- 
1.7.2.2

Re: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Laurent Pinchart]

Hi Bhupesh,

Thanks for the patch.

On Monday 12 March 2012 14:39:02 Bhupesh Sharma wrote:
> As the V4L2 based UVC webcam gadget (g_webcam) expects the
> 'videodev' to present when the 'webcam_bind' routine is called,
> so 'videodev' should be available as early as possible.
> 
> Now, when 'g_webcam' is built as a module (i.e. not a part of
> kernel) the late availability of 'videodev' is OK, but if
> 'g_webcam' is built statically as a part of the kernel,
> the kernel crashes (a sample crash dump using Designware 2.0 UDC
> is provided below).
> 
> To solve the same, this patch makes 'videodev_init' as a subsys initcall.
> 
> Kernel Crash Dump:
> ------------------

[snip]

> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
> ---
>  drivers/media/video/v4l2-dev.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
> index 96e9615..041804b 100644
> --- a/drivers/media/video/v4l2-dev.c
> +++ b/drivers/media/video/v4l2-dev.c
> @@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
>  	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
>  }
> 
> -module_init(videodev_init)
> +subsys_initcall(videodev_init);
>  module_exit(videodev_exit)
> 
>  MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");

Shouldn't drivers/media/media-devnode.c then use subsys_initcall() as well ?

-- 
Regards,

Laurent Pinchart

RE: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Bhupesh SHARMA]

Hi Laurent,

Thanks for your review comments.

> -----Original Message-----
> From: Laurent Pinchart [mailto:laurent.pinchart@ideasonboard.com]
> Sent: Monday, March 12, 2012 3:35 PM
> To: Bhupesh SHARMA
> Cc: linux-media@vger.kernel.org; spear-devel
> Subject: Re: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys
> initcall
> 
> Hi Bhupesh,
> 
> Thanks for the patch.
> 
> On Monday 12 March 2012 14:39:02 Bhupesh Sharma wrote:
> > As the V4L2 based UVC webcam gadget (g_webcam) expects the
> > 'videodev' to present when the 'webcam_bind' routine is called,
> > so 'videodev' should be available as early as possible.
> >
> > Now, when 'g_webcam' is built as a module (i.e. not a part of
> > kernel) the late availability of 'videodev' is OK, but if
> > 'g_webcam' is built statically as a part of the kernel,
> > the kernel crashes (a sample crash dump using Designware 2.0 UDC
> > is provided below).
> >
> > To solve the same, this patch makes 'videodev_init' as a subsys
> initcall.
> >
> > Kernel Crash Dump:
> > ------------------
> 
> [snip]
> 
> > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
> > ---
> >  drivers/media/video/v4l2-dev.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/media/video/v4l2-dev.c
> b/drivers/media/video/v4l2-dev.c
> > index 96e9615..041804b 100644
> > --- a/drivers/media/video/v4l2-dev.c
> > +++ b/drivers/media/video/v4l2-dev.c
> > @@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
> >  	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
> >  }
> >
> > -module_init(videodev_init)
> > +subsys_initcall(videodev_init);
> >  module_exit(videodev_exit)
> >
> >  MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab
> <mchehab@infradead.org>");
> 
> Shouldn't drivers/media/media-devnode.c then use subsys_initcall() as
> well ?
> 

Yes, it should. Do you want me to send a patch for the same also?

But I have no platform to check whether the Media Controller changes
for g_webcam work on a real platform (i.e. omap3isp), so can you
kindly test the patch I send for the same on your setup?

Regards,
Bhupesh

Re: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Laurent Pinchart]

Hi Bhupesh,

On Monday 12 March 2012 18:13:18 Bhupesh SHARMA wrote:
> On Monday, March 12, 2012 3:35 PM Laurent Pinchart wrote:
> > On Monday 12 March 2012 14:39:02 Bhupesh Sharma wrote:
> > > As the V4L2 based UVC webcam gadget (g_webcam) expects the
> > > 'videodev' to present when the 'webcam_bind' routine is called,
> > > so 'videodev' should be available as early as possible.
> > > 
> > > Now, when 'g_webcam' is built as a module (i.e. not a part of
> > > kernel) the late availability of 'videodev' is OK, but if
> > > 'g_webcam' is built statically as a part of the kernel,
> > > the kernel crashes (a sample crash dump using Designware 2.0 UDC
> > > is provided below).
> > > 
> > > To solve the same, this patch makes 'videodev_init' as a subsys
> > 
> > initcall.
> > 
> > > Kernel Crash Dump:
> > > ------------------
> > 
> > [snip]
> > 
> > > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
> > > ---
> > > 
> > >  drivers/media/video/v4l2-dev.c |    2 +-
> > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/drivers/media/video/v4l2-dev.c
> > 
> > b/drivers/media/video/v4l2-dev.c
> > 
> > > index 96e9615..041804b 100644
> > > --- a/drivers/media/video/v4l2-dev.c
> > > +++ b/drivers/media/video/v4l2-dev.c
> > > @@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
> > > 
> > >  	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
> > >  
> > >  }
> > > 
> > > -module_init(videodev_init)
> > > +subsys_initcall(videodev_init);
> > > 
> > >  module_exit(videodev_exit)
> > >  
> > >  MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab
> > 
> > <mchehab@infradead.org>");
> > 
> > Shouldn't drivers/media/media-devnode.c then use subsys_initcall() as
> > well ?
> 
> Yes, it should. Do you want me to send a patch for the same also?
> 
> But I have no platform to check whether the Media Controller changes
> for g_webcam work on a real platform (i.e. omap3isp), so can you
> kindly test the patch I send for the same on your setup?

I'll test both on the OMAP3 ISP and I'll send a patch for media-devnode.c.

-- 
Regards,

Laurent Pinchart

RE: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Bhupesh SHARMA]

Hi Laurent,

> -----Original Message-----
> From: Laurent Pinchart [mailto:laurent.pinchart@ideasonboard.com]
> Sent: Monday, March 12, 2012 3:54 PM
> To: Bhupesh SHARMA
> Cc: linux-media@vger.kernel.org; spear-devel
> Subject: Re: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys
> initcall
> 
> Hi Bhupesh,
> 
> On Monday 12 March 2012 18:13:18 Bhupesh SHARMA wrote:
> > On Monday, March 12, 2012 3:35 PM Laurent Pinchart wrote:
> > > On Monday 12 March 2012 14:39:02 Bhupesh Sharma wrote:
> > > > As the V4L2 based UVC webcam gadget (g_webcam) expects the
> > > > 'videodev' to present when the 'webcam_bind' routine is called,
> > > > so 'videodev' should be available as early as possible.
> > > >
> > > > Now, when 'g_webcam' is built as a module (i.e. not a part of
> > > > kernel) the late availability of 'videodev' is OK, but if
> > > > 'g_webcam' is built statically as a part of the kernel,
> > > > the kernel crashes (a sample crash dump using Designware 2.0 UDC
> > > > is provided below).
> > > >
> > > > To solve the same, this patch makes 'videodev_init' as a subsys
> > >
> > > initcall.
> > >
> > > > Kernel Crash Dump:
> > > > ------------------
> > >
> > > [snip]
> > >
> > > > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
> > > > ---
> > > >
> > > >  drivers/media/video/v4l2-dev.c |    2 +-
> > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > >
> > > > diff --git a/drivers/media/video/v4l2-dev.c
> > >
> > > b/drivers/media/video/v4l2-dev.c
> > >
> > > > index 96e9615..041804b 100644
> > > > --- a/drivers/media/video/v4l2-dev.c
> > > > +++ b/drivers/media/video/v4l2-dev.c
> > > > @@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
> > > >
> > > >  	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
> > > >
> > > >  }
> > > >
> > > > -module_init(videodev_init)
> > > > +subsys_initcall(videodev_init);
> > > >
> > > >  module_exit(videodev_exit)
> > > >
> > > >  MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab
> > >
> > > <mchehab@infradead.org>");
> > >
> > > Shouldn't drivers/media/media-devnode.c then use subsys_initcall()
> as
> > > well ?
> >
> > Yes, it should. Do you want me to send a patch for the same also?
> >
> > But I have no platform to check whether the Media Controller changes
> > for g_webcam work on a real platform (i.e. omap3isp), so can you
> > kindly test the patch I send for the same on your setup?
> 
> I'll test both on the OMAP3 ISP and I'll send a patch for media-
> devnode.c.

Ok thanks.

Regards,
Bhupesh

Re: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Laurent Pinchart]

On Monday 12 March 2012 14:39:02 Bhupesh Sharma wrote:
> As the V4L2 based UVC webcam gadget (g_webcam) expects the
> 'videodev' to present when the 'webcam_bind' routine is called,
> so 'videodev' should be available as early as possible.
> 
> Now, when 'g_webcam' is built as a module (i.e. not a part of
> kernel) the late availability of 'videodev' is OK, but if
> 'g_webcam' is built statically as a part of the kernel,
> the kernel crashes (a sample crash dump using Designware 2.0 UDC
> is provided below).
> 
> To solve the same, this patch makes 'videodev_init' as a subsys initcall.

[snip]

> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>

Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/video/v4l2-dev.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
> index 96e9615..041804b 100644
> --- a/drivers/media/video/v4l2-dev.c
> +++ b/drivers/media/video/v4l2-dev.c
> @@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
>  	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
>  }
> 
> -module_init(videodev_init)
> +subsys_initcall(videodev_init);
>  module_exit(videodev_exit)
> 
>  MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");

-- 
Regards,

Laurent Pinchart

[PATCH] media: Initialize the media core with subsys_initcall()

[Laurent Pinchart]

Media-related drivers living outside drivers/media/ (such as the UVC
gadget driver in drivers/usb/gadget/) rely on the media core being
initialized before they're probed. As drivers/usb/ is linked before
drivers/media/, this is currently not the case and will lead to crashes
if the drivers are not compiled as modules.

Register media_devnode_init() as a subsys_initcall() instead of
module_init() to fix this.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/media-devnode.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Bhupesh, do you plan to send a pull request with your "V4L/v4l2-dev: Make
'videodev_init' as a subsys initcall" patch, or would you like me to take it
in my tree ? I'd like both patches to go in at the same time, with this one
coming first to avoid any risk of bisection issue.

diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c
index 7b42ace..421cf73 100644
--- a/drivers/media/media-devnode.c
+++ b/drivers/media/media-devnode.c
@@ -312,7 +312,7 @@ static void __exit media_devnode_exit(void)
 	unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
 }
 
-module_init(media_devnode_init)
+subsys_initcall(media_devnode_init);
 module_exit(media_devnode_exit)
 
 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
-- 
Regards,

Laurent Pinchart

RE: [PATCH] media: Initialize the media core with subsys_initcall()

[Bhupesh SHARMA]

Hi Laurent,

Thanks for the patch.

> -----Original Message-----
> From: Laurent Pinchart [mailto:laurent.pinchart@ideasonboard.com]
> Sent: Monday, March 12, 2012 7:33 PM
> To: linux-media@vger.kernel.org
> Cc: Bhupesh SHARMA
> Subject: [PATCH] media: Initialize the media core with
> subsys_initcall()
> 
> Media-related drivers living outside drivers/media/ (such as the UVC
> gadget driver in drivers/usb/gadget/) rely on the media core being
> initialized before they're probed. As drivers/usb/ is linked before
> drivers/media/, this is currently not the case and will lead to crashes
> if the drivers are not compiled as modules.
> 
> Register media_devnode_init() as a subsys_initcall() instead of
> module_init() to fix this.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/media-devnode.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

> Bhupesh, do you plan to send a pull request with your "V4L/v4l2-dev:
> Make
> 'videodev_init' as a subsys initcall" patch, or would you like me to
> take it
> in my tree ? I'd like both patches to go in at the same time, with this
> one
> coming first to avoid any risk of bisection issue.

I would prefer that you take my patch also in your tree and have
a single pull request for both the patches as they solve the same
issue and hence must be pulled at the same time.

For your patch:
Acked-By: Bhupesh Sharma <bhupesh.sharma@st.com>

> 
> diff --git a/drivers/media/media-devnode.c b/drivers/media/media-
> devnode.c
> index 7b42ace..421cf73 100644
> --- a/drivers/media/media-devnode.c
> +++ b/drivers/media/media-devnode.c
> @@ -312,7 +312,7 @@ static void __exit media_devnode_exit(void)
>  	unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
>  }
> 
> -module_init(media_devnode_init)
> +subsys_initcall(media_devnode_init);
>  module_exit(media_devnode_exit)
> 
>  MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
> --

Regards,
Bhupesh

Re: [PATCH] media: Initialize the media core with subsys_initcall()

[Laurent Pinchart]

Hi Bhupesh,

On Tuesday 13 March 2012 11:31:31 Bhupesh SHARMA wrote:
> Hi Laurent,
> 
> Thanks for the patch.
> 
> > -----Original Message-----
> > From: Laurent Pinchart [mailto:laurent.pinchart@ideasonboard.com]
> > Sent: Monday, March 12, 2012 7:33 PM
> > To: linux-media@vger.kernel.org
> > Cc: Bhupesh SHARMA
> > Subject: [PATCH] media: Initialize the media core with
> > subsys_initcall()
> > 
> > Media-related drivers living outside drivers/media/ (such as the UVC
> > gadget driver in drivers/usb/gadget/) rely on the media core being
> > initialized before they're probed. As drivers/usb/ is linked before
> > drivers/media/, this is currently not the case and will lead to crashes
> > if the drivers are not compiled as modules.
> > 
> > Register media_devnode_init() as a subsys_initcall() instead of
> > module_init() to fix this.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> > 
> >  drivers/media/media-devnode.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > Bhupesh, do you plan to send a pull request with your "V4L/v4l2-dev:
> > Make
> > 'videodev_init' as a subsys initcall" patch, or would you like me to
> > take it
> > in my tree ? I'd like both patches to go in at the same time, with this
> > one
> > coming first to avoid any risk of bisection issue.
> 
> I would prefer that you take my patch also in your tree and have
> a single pull request for both the patches as they solve the same
> issue and hence must be pulled at the same time.

OK. I've applied your patch to my tree, I'll send a pull request tomorrow.

> For your patch:
> Acked-By: Bhupesh Sharma <bhupesh.sharma@st.com>

Thanks.

> > diff --git a/drivers/media/media-devnode.c b/drivers/media/media-
> > devnode.c
> > index 7b42ace..421cf73 100644
> > --- a/drivers/media/media-devnode.c
> > +++ b/drivers/media/media-devnode.c
> > @@ -312,7 +312,7 @@ static void __exit media_devnode_exit(void)
> > 
> >  	unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
> >  
> >  }
> > 
> > -module_init(media_devnode_init)
> > +subsys_initcall(media_devnode_init);
> > 
> >  module_exit(media_devnode_exit)
> >  
> >  MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
> > 
> > --

-- 
Regards,

Laurent Pinchart

Re: [PATCH] media: Initialize the media core with subsys_initcall()

[Sakari Ailus]

Hi Laurent,

Thanks for the patch!

On Mon, Mar 12, 2012 at 03:02:47PM +0100, Laurent Pinchart wrote:
> Media-related drivers living outside drivers/media/ (such as the UVC
> gadget driver in drivers/usb/gadget/) rely on the media core being
> initialized before they're probed. As drivers/usb/ is linked before
> drivers/media/, this is currently not the case and will lead to crashes
> if the drivers are not compiled as modules.
> 
> Register media_devnode_init() as a subsys_initcall() instead of
> module_init() to fix this.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/media-devnode.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Tested-by: Sakari Ailus <sakari.ailus@iki.fi>

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi	jabber/XMPP/Gmail: sailus@retiisi.org.uk

Re: [PATCH 1/1] V4L/v4l2-dev: Make 'videodev_init' as a subsys initcall

[Sakari Ailus]

Hi Bhupesh,

On Mon, Mar 12, 2012 at 02:39:02PM +0530, Bhupesh Sharma wrote:
> As the V4L2 based UVC webcam gadget (g_webcam) expects the
> 'videodev' to present when the 'webcam_bind' routine is called,
> so 'videodev' should be available as early as possible.
> 
> Now, when 'g_webcam' is built as a module (i.e. not a part of
> kernel) the late availability of 'videodev' is OK, but if
> 'g_webcam' is built statically as a part of the kernel,
> the kernel crashes (a sample crash dump using Designware 2.0 UDC
> is provided below).
> 
> To solve the same, this patch makes 'videodev_init' as a subsys initcall.
> 
> Kernel Crash Dump:
> ------------------
> 
> designware_udc designware_udc: Device Synopsys UDC probed csr 90810000: plug 90812000
> g_webcam gadget: uvc_function_bind
> Unable to handle kernel NULL pointer dereference at virtual address 000000e4
> pgd = 80004000
> [000000e4] *pgd=00000000
> Internal error: Oops: 5 [#1] SMP
> Modules linked in:
> CPU: 0    Not tainted  (3.3.0-rc3-13888-ge774c03-dirty #20)
> PC is at do_raw_spin_lock+0x10/0x16c
> LR is at _raw_spin_lock+0x10/0x14
> pc : [<8019e344>]    lr : [<804095c0>]    psr: 60000013
> sp : 8f839d20  ip : 8f839d50  fp : 8f839d4c
> r10: 80760a94  r9 : 8042de98  r8 : 00000154
> r7 : 80760e94  r6 : 805cfc10  r5 : 8fb6a008  r4 : 8fb6a008
> r3 : 805dd0c8  r2 : 8f839d48  r1 : 805cfc08  r0 : 000000e0
> Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
> Control: 10c5387d  Table: 0000404a  DAC: 00000015
> Process swapper/0 (pid: 1, stack limit = 0x8f8382f0)
> Stack: (0x8f839d20 to 0x8f83a000)
> 9d20: ffffffff ffffffff 8fb6a008 8fb6a008 805cfc10 80760e94 00000154 8042de98
> 9d40: 8f839d5c 8f839d50 804095c0 8019e340 8f839d7c 8f839d60 80222b28 804095bc
> 9d60: 8fb12b80 8fb6a008 8fb6a010 805cfc08 8f839dc4 8f839d80 80223db8 80222adc
> 9d80: 8f839dac 8f839d90 8022baa0 8019e2e8 8fb6a008 8075e7f4 8fb6a008 8fb6a008
> 9da0: 00000000 8fb6a008 80760e94 00000154 8042de98 80760a94 8f839ddc 8f839dc8
> 9dc0: 802242a8 80223d1c 8fb12b80 8fb6a000 8f839e1c 8f839de0 8030132c 80224298
> 9de0: 80223ce8 803f2ee8 00000001 804f7750 8f839e1c 8f824008 805cff20 8f824000
> 9e00: 8fb6a000 ffffffff 00000000 8f8d4880 8f839e4c 8f839e20 80562e3c 80301100
> 9e20: 00000000 8fb13140 8f824008 805cff20 8042aa68 8f824000 8042aa8c 805e4d40
> 9e40: 8f839e64 8f839e50 802d20c4 80562ba8 805d0058 805cff20 8f839e8c 8f839e68
> 9e60: 80563034 802d206c 8042aa8c 805cff20 8f8d4880 00000000 805cfc08 8fb12a40
> 9e80: 8f839e9c 8f839e90 805630c4 80562ec4 8f839ebc 8f839ea0 802d2364 805630b0
> 9ea0: 805cfeac 8f8d4880 805cfbe8 807605e8 8f839ed4 8f839ec0 80562b3c 802d22cc
> 9ec0: 80562ac4 8f8d4880 8f839f04 8f839ed8 802d0b40 80562ad0 8f839ef4 805cff90
> 9ee0: 805cff90 805cfb98 00000000 00000000 805cfbe8 805e4d40 8f839f3c 8f839f08
> 9f00: 802cd078 802d0a18 00000000 802d0a0c 00000000 8fb9ba00 802d0a0c 805cff90
> 9f20: 00000013 00000000 00000000 805e4d40 8f839f5c 8f839f40 802cf390 802ccff0
> 9f40: 00000003 00000003 804fb598 00000000 8f839f74 8f839f60 802d2554 802cf2a0
> 9f60: 8f838000 8057731c 8f839f84 8f839f78 80562b90 802d24d0 8f839fdc 8f839f88
> 9f80: 800085d4 80562b84 805af2ac 805af2ac 80562b78 00000000 00000013 00000000
> 9fa0: 00000000 00000000 8f839fc4 8f839fb8 80043dd0 8057706c 8057731c 8002875c
> 9fc0: 00000013 00000000 00000000 00000000 8f839ff4 8f839fe0 805468d4 800085a0
> 9fe0: 00000000 80546840 00000000 8f839ff8 8002875c 8054684c 51155555 55545555
> Backtrace:
> [<8019e334>] (do_raw_spin_lock+0x0/0x16c) from [<804095c0>] (_raw_spin_lock+0x10/0x14)
>  r9:8042de98 r8:00000154 r7:80760e94 r6:805cfc10 r5:8fb6a008
> r4:8fb6a008
> [<804095b0>] (_raw_spin_lock+0x0/0x14) from [<80222b28>] (get_device_parent+0x58/0x1c0)
> [<80222ad0>] (get_device_parent+0x0/0x1c0) from [<80223db8>] (device_add+0xa8/0x57c)
>  r6:805cfc08 r5:8fb6a010 r4:8fb6a008 r3:8fb12b80
> [<80223d10>] (device_add+0x0/0x57c) from [<802242a8>] (device_register+0x1c/0x20)
> [<8022428c>] (device_register+0x0/0x20) from [<8030132c>] (__video_register_device+0x238/0x484)
>  r4:8fb6a000 r3:8fb12b80
> [<803010f4>] (__video_register_device+0x0/0x484) from [<80562e3c>] (uvc_function_bind+0x2a0/0x31c)
> [<80562b9c>] (uvc_function_bind+0x0/0x31c) from [<802d20c4>] (usb_add_function+0x64/0x118)
> [<802d2060>] (usb_add_function+0x0/0x118) from [<80563034>] (uvc_bind_config+0x17c/0x1ec)
>  r5:805cff20 r4:805d0058
> [<80562eb8>] (uvc_bind_config+0x0/0x1ec) from [<805630c4>] (webcam_config_bind+0x20/0x28)
>  r8:8fb12a40 r7:805cfc08 r6:00000000 r5:8f8d4880 r4:805cff20
> r3:8042aa8c
> [<805630a4>] (webcam_config_bind+0x0/0x28) from [<802d2364>] (usb_add_config+0xa4/0x124)
> [<802d22c0>] (usb_add_config+0x0/0x124) from [<80562b3c>] (webcam_bind+0x78/0xb4)
>  r6:807605e8 r5:805cfbe8 r4:8f8d4880 r3:805cfeac
> [<80562ac4>] (webcam_bind+0x0/0xb4) from [<802d0b40>] (composite_bind+0x134/0x308)
>  r4:8f8d4880 r3:80562ac4
> [<802d0a0c>] (composite_bind+0x0/0x308) from [<802cd078>] (dw_udc_start+0x94/0x2bc)
> [<802ccfe4>] (dw_udc_start+0x0/0x2bc) from [<802cf390>] (usb_gadget_probe_driver+0xfc/0x180)
> [<802cf294>] (usb_gadget_probe_driver+0x0/0x180) from [<802d2554>] (usb_composite_probe+0x90/0xb4)
>  r6:00000000 r5:804fb598 r4:00000003 r3:00000003
> [<802d24c4>] (usb_composite_probe+0x0/0xb4) from [<80562b90>] (webcam_init+0x18/0x24)
>  r5:8057731c r4:8f838000
> [<80562b78>] (webcam_init+0x0/0x24) from [<800085d4>] (do_one_initcall+0x40/0x184)
> [<80008594>] (do_one_initcall+0x0/0x184) from [<805468d4>] (kernel_init+0x94/0x134)
> [<80546840>] (kernel_init+0x0/0x134) from [<8002875c>] (do_exit+0x0/0x6f8)
>  r5:80546840 r4:00000000
> Code: e1a0c00d e92ddbf0 e24cb004 e24dd008 (e5902004)
> ---[ end trace 7ecca37f36fbdc06 ]---
> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>

Thanks!

Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Tested-by: Sakari Ailus <sakari.ailus@iki.fi>

> ---
>  drivers/media/video/v4l2-dev.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
> index 96e9615..041804b 100644
> --- a/drivers/media/video/v4l2-dev.c
> +++ b/drivers/media/video/v4l2-dev.c
> @@ -788,7 +788,7 @@ static void __exit videodev_exit(void)
>  	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
>  }
>  
> -module_init(videodev_init)
> +subsys_initcall(videodev_init);
>  module_exit(videodev_exit)
>  
>  MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
> -- 
> 1.7.2.2
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Cheers,

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi	jabber/XMPP/Gmail: sailus@retiisi.org.uk