* Trace
@ 2008-09-01 9:16 Sébastien Chrétien
2008-09-01 9:23 ` Trace Benjamin Herrenschmidt
2008-09-01 10:00 ` Trace Jenkins, Clive
0 siblings, 2 replies; 14+ messages in thread
From: Sébastien Chrétien @ 2008-09-01 9:16 UTC (permalink / raw)
To: linuxppc-dev
[-- Attachment #1: Type: text/plain, Size: 1766 bytes --]
Hello,
I am triying to write a tty_driver under ppc. And I get a kernel panic.
Can somebody explain me how finding the source of the error with a kernel
panic trace :
thanks
Unable to handle kernel paging request for data at address 0x575555f9
Faulting instruction address: 0xc0110ddc
Oops: Kernel access of bad area, sig: 11 [#1]
Modules linked in:
NIP: c0110ddc LR: c011118c CTR: 00000000
REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
DAR: 575555f9, DSISR: 40000000
TASK = cf01c000[1] 'swapper' THREAD: cf01a000
GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000
c01d0000
GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00
007fff00
GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000
00800000
GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300
57555541
NIP [c0110ddc] init_dev+0x2bc/0x584
LR [c011118c] tty_open+0xe8/0x3e0
Call Trace:
[cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
[cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
[cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
[cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
[cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
[cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
[cf01bf10] [c00700b4] do_sys_open+0x74/0x114
[cf01bf40] [c0003c94] init_post+0x34/0x258
[cf01bf60] [c019ca64] kernel_init+0x258/0x270
[cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
Instruction dump:
7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
---[ end trace b7795a387aeb7786 ]---
Kernel panic - not syncing: Attempted to kill init!
allocation failed: out of vmalloc space - use vmalloc=<size> to increase
size.
[-- Attachment #2: Type: text/html, Size: 1976 bytes --]
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-01 9:16 Trace Sébastien Chrétien
@ 2008-09-01 9:23 ` Benjamin Herrenschmidt
2008-09-01 10:00 ` Trace Jenkins, Clive
1 sibling, 0 replies; 14+ messages in thread
From: Benjamin Herrenschmidt @ 2008-09-01 9:23 UTC (permalink / raw)
To: Sébastien Chrétien; +Cc: linuxppc-dev
On Mon, 2008-09-01 at 11:16 +0200, Sébastien Chrétien wrote:
> Hello,
>
> I am triying to write a tty_driver under ppc. And I get a kernel
> panic.
> Can somebody explain me how finding the source of the error with a
> kernel panic trace :
> thanks
What kind of device are you writing a tty driver for ?
I don't see anything much relevant in your backtrace, you went through a
crap pointer in init_dev, could be anything at this stage...
Can you post your driver to the list ?
Ben.
> Unable to handle kernel paging request for data at address 0x575555f9
> Faulting instruction address: 0xc0110ddc
> Oops: Kernel access of bad area, sig: 11 [#1]
> Modules linked in:
> NIP: c0110ddc LR: c011118c CTR: 00000000
> REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
> MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
> DAR: 575555f9, DSISR: 40000000
> TASK = cf01c000[1] 'swapper' THREAD: cf01a000
> GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000
> c01d0000
> GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00
> 007fff00
> GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000
> 00800000
> GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300
> 57555541
> NIP [c0110ddc] init_dev+0x2bc/0x584
> LR [c011118c] tty_open+0xe8/0x3e0
> Call Trace:
> [cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
> [cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
> [cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
> [cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
> [cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
> [cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
> [cf01bf10] [c00700b4] do_sys_open+0x74/0x114
> [cf01bf40] [c0003c94] init_post+0x34/0x258
> [cf01bf60] [c019ca64] kernel_init+0x258/0x270
> [cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
> Instruction dump:
> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062
> 2f800001
> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0
> 801e0060
> ---[ end trace b7795a387aeb7786 ]---
> Kernel panic - not syncing: Attempted to kill init!
> allocation failed: out of vmalloc space - use vmalloc=<size> to
> increase size.
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
^ permalink raw reply [flat|nested] 14+ messages in thread
* RE: Trace
2008-09-01 9:16 Trace Sébastien Chrétien
2008-09-01 9:23 ` Trace Benjamin Herrenschmidt
@ 2008-09-01 10:00 ` Jenkins, Clive
2008-09-01 12:25 ` Trace Sébastien Chrétien
1 sibling, 1 reply; 14+ messages in thread
From: Jenkins, Clive @ 2008-09-01 10:00 UTC (permalink / raw)
To: Sébastien Chrétien, linuxppc-dev
The instruction that caused the fault is at this address:
> NIP [c0110ddc] init_dev+0x2bc/0x584
The hex value of the instruction is also highlighted between <> here:
> Instruction dump:
> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 =
2f800001=20
> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 =
801e0060=20
Disassemble your kernel and look at offset 0x2BC relative to the label =
init_dev
=20
________________________________
From: linuxppc-dev-bounces+clive.jenkins=3Dxerox.com@ozlabs.org =
[mailto:linuxppc-dev-bounces+clive.jenkins=3Dxerox.com@ozlabs.org] On =
Behalf Of S=E9bastien Chr=E9tien
Sent: 01 September 2008 10:16
To: linuxppc-dev@ozlabs.org
Subject: Trace
Hello,
I am triying to write a tty_driver under ppc. And I get a kernel panic.
Can somebody explain me how finding the source of the error with a =
kernel panic trace :=20
thanks
Unable to handle kernel paging request for data at address 0x575555f9
Faulting instruction address: 0xc0110ddc
Oops: Kernel access of bad area, sig: 11 [#1]
Modules linked in:
NIP: c0110ddc LR: c011118c CTR: 00000000
REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
DAR: 575555f9, DSISR: 40000000
TASK =3D cf01c000[1] 'swapper' THREAD: cf01a000
GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000 =
c01d0000=20
GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00 =
007fff00=20
GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000 =
00800000=20
GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300 =
57555541=20
NIP [c0110ddc] init_dev+0x2bc/0x584
LR [c011118c] tty_open+0xe8/0x3e0
Call Trace:
[cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
[cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
[cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
[cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
[cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
[cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
[cf01bf10] [c00700b4] do_sys_open+0x74/0x114
[cf01bf40] [c0003c94] init_post+0x34/0x258
[cf01bf60] [c019ca64] kernel_init+0x258/0x270
[cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
Instruction dump:
7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001=20
409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 =
801e0060=20
---[ end trace b7795a387aeb7786 ]---
Kernel panic - not syncing: Attempted to kill init!
allocation failed: out of vmalloc space - use vmalloc=3D<size> to =
increase size.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-01 10:00 ` Trace Jenkins, Clive
@ 2008-09-01 12:25 ` Sébastien Chrétien
2008-09-01 13:54 ` Trace Jenkins, Clive
0 siblings, 1 reply; 14+ messages in thread
From: Sébastien Chrétien @ 2008-09-01 12:25 UTC (permalink / raw)
To: Jenkins, Clive; +Cc: linuxppc-dev
[-- Attachment #1: Type: text/plain, Size: 3112 bytes --]
I found where is the failure with your advices
In init_dev (tty_io.c), init_dev calls "tty = driver->ttys[idx]"
after this call, tty value is : tty = 0x57555541
Have I to initialize driver->ttys in my driver. If yes, how have I to
Initialize this ?
The driver tty is used in order to have a console on my serial port.
Thanks for your help
2008/9/1, Jenkins, Clive <Clive.Jenkins@xerox.com>:
>
> The instruction that caused the fault is at this address:
>
> > NIP [c0110ddc] init_dev+0x2bc/0x584
>
>
> The hex value of the instruction is also highlighted between <> here:
>
> > Instruction dump:
> > 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
> > 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
>
>
> Disassemble your kernel and look at offset 0x2BC relative to the label
> init_dev
>
> ________________________________
>
> From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:
> linuxppc-dev-bounces+clive.jenkins <linuxppc-dev-bounces%2Bclive.jenkins>=
> xerox.com@ozlabs.org] On Behalf Of Sébastien Chrétien
> Sent: 01 September 2008 10:16
> To: linuxppc-dev@ozlabs.org
> Subject: Trace
>
>
>
> Hello,
>
> I am triying to write a tty_driver under ppc. And I get a kernel panic.
> Can somebody explain me how finding the source of the error with a kernel
> panic trace :
> thanks
>
> Unable to handle kernel paging request for data at address 0x575555f9
> Faulting instruction address: 0xc0110ddc
> Oops: Kernel access of bad area, sig: 11 [#1]
> Modules linked in:
> NIP: c0110ddc LR: c011118c CTR: 00000000
> REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
> MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
> DAR: 575555f9, DSISR: 40000000
> TASK = cf01c000[1] 'swapper' THREAD: cf01a000
> GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000
> c01d0000
> GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00
> 007fff00
> GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000
> 00800000
> GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300
> 57555541
> NIP [c0110ddc] init_dev+0x2bc/0x584
> LR [c011118c] tty_open+0xe8/0x3e0
> Call Trace:
> [cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
> [cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
> [cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
> [cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
> [cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
> [cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
> [cf01bf10] [c00700b4] do_sys_open+0x74/0x114
> [cf01bf40] [c0003c94] init_post+0x34/0x258
> [cf01bf60] [c019ca64] kernel_init+0x258/0x270
> [cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
> Instruction dump:
> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
> ---[ end trace b7795a387aeb7786 ]---
> Kernel panic - not syncing: Attempted to kill init!
> allocation failed: out of vmalloc space - use vmalloc=<size> to increase
> size.
>
>
[-- Attachment #2: Type: text/html, Size: 3759 bytes --]
^ permalink raw reply [flat|nested] 14+ messages in thread
* RE: Trace
2008-09-01 12:25 ` Trace Sébastien Chrétien
@ 2008-09-01 13:54 ` Jenkins, Clive
2008-09-01 13:58 ` Trace Jenkins, Clive
0 siblings, 1 reply; 14+ messages in thread
From: Jenkins, Clive @ 2008-09-01 13:54 UTC (permalink / raw)
To: Sébastien Chrétien; +Cc: linuxppc-dev
I'm not sure that is a failure. Why can't tty have value 0x57555541 ?
I think the code in tty_io.c initialises driver->ttys and you shouldn't =
need to do anything in your driver.
=20
If you are not already aware, a useful way to explore kernel code is to =
use LXR:
http://lxr.linux.no/linux+v2.6.26/include/linux/tty_driver.h#L212
This may help you understand the tty code.
=20
Good luck!
=20
________________________________
From: S=E9bastien Chr=E9tien =
[mailto:sebastien.chretien.enseirb@gmail.com]=20
Sent: 01 September 2008 13:25
To: Jenkins, Clive
Cc: linuxppc-dev@ozlabs.org
Subject: Re: Trace
I found where is the failure with your advices=20
In init_dev (tty_io.c), init_dev calls "tty =3D driver->ttys[idx]"
after this call, tty value is : tty =3D 0x57555541
Have I to initialize driver->ttys in my driver. If yes, how have I to =
Initialize this ?
The driver tty is used in order to have a console on my serial port.
Thanks for your help
2008/9/1, Jenkins, Clive <Clive.Jenkins@xerox.com>:=20
The instruction that caused the fault is at this address:
=09
> NIP [c0110ddc] init_dev+0x2bc/0x584
=09
=09
The hex value of the instruction is also highlighted between <> here:
=09
> Instruction dump:
> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 =
2f800001
> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 =
801e0060
=09
=09
Disassemble your kernel and look at offset 0x2BC relative to the label =
init_dev
=09
________________________________
=09
From: linuxppc-dev-bounces+clive.jenkins=3Dxerox.com@ozlabs.org =
[mailto:linuxppc-dev-bounces+clive.jenkins =
<mailto:linuxppc-dev-bounces%2Bclive.jenkins> =3Dxerox.com@ozlabs.org] =
On Behalf Of S=E9bastien Chr=E9tien
Sent: 01 September 2008 10:16
To: linuxppc-dev@ozlabs.org
Subject: Trace
=09
=09
=09
Hello,
=09
I am triying to write a tty_driver under ppc. And I get a kernel panic.
Can somebody explain me how finding the source of the error with a =
kernel panic trace :
thanks
=09
Unable to handle kernel paging request for data at address 0x575555f9
Faulting instruction address: 0xc0110ddc
Oops: Kernel access of bad area, sig: 11 [#1]
Modules linked in:
NIP: c0110ddc LR: c011118c CTR: 00000000
REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
DAR: 575555f9, DSISR: 40000000
TASK =3D cf01c000[1] 'swapper' THREAD: cf01a000
GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000 =
c01d0000
GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00 =
007fff00
GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000 =
00800000
GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300 =
57555541
NIP [c0110ddc] init_dev+0x2bc/0x584
LR [c011118c] tty_open+0xe8/0x3e0
Call Trace:
[cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
[cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
[cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
[cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
[cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
[cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
[cf01bf10] [c00700b4] do_sys_open+0x74/0x114
[cf01bf40] [c0003c94] init_post+0x34/0x258
[cf01bf60] [c019ca64] kernel_init+0x258/0x270
[cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
Instruction dump:
7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 =
801e0060
---[ end trace b7795a387aeb7786 ]---
Kernel panic - not syncing: Attempted to kill init!
allocation failed: out of vmalloc space - use vmalloc=3D<size> to =
increase size.
=09
=09
^ permalink raw reply [flat|nested] 14+ messages in thread
* RE: Trace
2008-09-01 13:54 ` Trace Jenkins, Clive
@ 2008-09-01 13:58 ` Jenkins, Clive
2008-09-01 16:33 ` Trace Sébastien Chrétien
0 siblings, 1 reply; 14+ messages in thread
From: Jenkins, Clive @ 2008-09-01 13:58 UTC (permalink / raw)
To: Jenkins, Clive, Sébastien Chrétien; +Cc: linuxppc-dev
> Why can't tty have value 0x57555541 ?
To answer my own question, because it ends in 1 and is not word-aligned!
-----Original Message-----
From: linuxppc-dev-bounces+clive.jenkins=3Dxerox.com@ozlabs.org =
[mailto:linuxppc-dev-bounces+clive.jenkins=3Dxerox.com@ozlabs.org] On =
Behalf Of Jenkins, Clive
Sent: 01 September 2008 14:54
To: S=E9bastien Chr=E9tien
Cc: linuxppc-dev@ozlabs.org
Subject: RE: Trace
I'm not sure that is a failure. Why can't tty have value 0x57555541 ?
I think the code in tty_io.c initialises driver->ttys and you shouldn't =
need to do anything in your driver.
=20
If you are not already aware, a useful way to explore kernel code is to =
use LXR:
http://lxr.linux.no/linux+v2.6.26/include/linux/tty_driver.h#L212
This may help you understand the tty code.
=20
Good luck!
=20
________________________________
From: S=E9bastien Chr=E9tien =
[mailto:sebastien.chretien.enseirb@gmail.com]=20
Sent: 01 September 2008 13:25
To: Jenkins, Clive
Cc: linuxppc-dev@ozlabs.org
Subject: Re: Trace
I found where is the failure with your advices=20
In init_dev (tty_io.c), init_dev calls "tty =3D driver->ttys[idx]"
after this call, tty value is : tty =3D 0x57555541
Have I to initialize driver->ttys in my driver. If yes, how have I to =
Initialize this ?
The driver tty is used in order to have a console on my serial port.
Thanks for your help
2008/9/1, Jenkins, Clive <Clive.Jenkins@xerox.com>:=20
The instruction that caused the fault is at this address:
=09
> NIP [c0110ddc] init_dev+0x2bc/0x584
=09
=09
The hex value of the instruction is also highlighted between <> here:
=09
> Instruction dump:
> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 =
2f800001
> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 =
801e0060
=09
=09
Disassemble your kernel and look at offset 0x2BC relative to the label =
init_dev
=09
________________________________
=09
From: linuxppc-dev-bounces+clive.jenkins=3Dxerox.com@ozlabs.org =
[mailto:linuxppc-dev-bounces+clive.jenkins =
<mailto:linuxppc-dev-bounces%2Bclive.jenkins> =3Dxerox.com@ozlabs.org] =
On Behalf Of S=E9bastien Chr=E9tien
Sent: 01 September 2008 10:16
To: linuxppc-dev@ozlabs.org
Subject: Trace
=09
=09
=09
Hello,
=09
I am triying to write a tty_driver under ppc. And I get a kernel panic.
Can somebody explain me how finding the source of the error with a =
kernel panic trace :
thanks
=09
Unable to handle kernel paging request for data at address 0x575555f9
Faulting instruction address: 0xc0110ddc
Oops: Kernel access of bad area, sig: 11 [#1]
Modules linked in:
NIP: c0110ddc LR: c011118c CTR: 00000000
REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
DAR: 575555f9, DSISR: 40000000
TASK =3D cf01c000[1] 'swapper' THREAD: cf01a000
GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000 =
c01d0000
GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00 =
007fff00
GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000 =
00800000
GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300 =
57555541
NIP [c0110ddc] init_dev+0x2bc/0x584
LR [c011118c] tty_open+0xe8/0x3e0
Call Trace:
[cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
[cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
[cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
[cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
[cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
[cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
[cf01bf10] [c00700b4] do_sys_open+0x74/0x114
[cf01bf40] [c0003c94] init_post+0x34/0x258
[cf01bf60] [c019ca64] kernel_init+0x258/0x270
[cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
Instruction dump:
7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 =
801e0060
---[ end trace b7795a387aeb7786 ]---
Kernel panic - not syncing: Attempted to kill init!
allocation failed: out of vmalloc space - use vmalloc=3D<size> to =
increase size.
=09
=09
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-01 13:58 ` Trace Jenkins, Clive
@ 2008-09-01 16:33 ` Sébastien Chrétien
2008-09-02 0:13 ` Trace Benjamin Herrenschmidt
0 siblings, 1 reply; 14+ messages in thread
From: Sébastien Chrétien @ 2008-09-01 16:33 UTC (permalink / raw)
To: Jenkins, Clive; +Cc: Sébastien Chrétien, linuxppc-dev
Thanks for your answer.
Your analyse of ttys is very well. It was not my answer. All adresses in
system.map begin with 0xc... So I think it is the case for ttys too.
I found the mistake. It came from my board_device function in struct
console(console ->device). It didn't change the value of the parameter
int* index.
So Linux loaded a tty_structure which was in tiny_ttys[-1]
console.h is not very well documented about this.
Thanks
Sébastien Chrétien
Jenkins, Clive a écrit :
>> Why can't tty have value 0x57555541 ?
>>
> To answer my own question, because it ends in 1 and is not word-aligned!
>
> -----Original Message-----
> From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org] On Behalf Of Jenkins, Clive
> Sent: 01 September 2008 14:54
> To: Sébastien Chrétien
> Cc: linuxppc-dev@ozlabs.org
> Subject: RE: Trace
>
> I'm not sure that is a failure. Why can't tty have value 0x57555541 ?
>
> I think the code in tty_io.c initialises driver->ttys and you shouldn't need to do anything in your driver.
>
> If you are not already aware, a useful way to explore kernel code is to use LXR:
> http://lxr.linux.no/linux+v2.6.26/include/linux/tty_driver.h#L212
> This may help you understand the tty code.
>
> Good luck!
>
> ________________________________
>
> From: Sébastien Chrétien [mailto:sebastien.chretien.enseirb@gmail.com]
> Sent: 01 September 2008 13:25
> To: Jenkins, Clive
> Cc: linuxppc-dev@ozlabs.org
> Subject: Re: Trace
>
>
> I found where is the failure with your advices
> In init_dev (tty_io.c), init_dev calls "tty = driver->ttys[idx]"
> after this call, tty value is : tty = 0x57555541
>
> Have I to initialize driver->ttys in my driver. If yes, how have I to Initialize this ?
>
> The driver tty is used in order to have a console on my serial port.
> Thanks for your help
>
>
>
> 2008/9/1, Jenkins, Clive <Clive.Jenkins@xerox.com>:
>
> The instruction that caused the fault is at this address:
>
> > NIP [c0110ddc] init_dev+0x2bc/0x584
>
>
> The hex value of the instruction is also highlighted between <> here:
>
> > Instruction dump:
> > 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
> > 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
>
>
> Disassemble your kernel and look at offset 0x2BC relative to the label init_dev
>
> ________________________________
>
> From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:linuxppc-dev-bounces+clive.jenkins <mailto:linuxppc-dev-bounces%2Bclive.jenkins> =xerox.com@ozlabs.org] On Behalf Of Sébastien Chrétien
> Sent: 01 September 2008 10:16
> To: linuxppc-dev@ozlabs.org
> Subject: Trace
>
>
>
> Hello,
>
> I am triying to write a tty_driver under ppc. And I get a kernel panic.
> Can somebody explain me how finding the source of the error with a kernel panic trace :
> thanks
>
> Unable to handle kernel paging request for data at address 0x575555f9
> Faulting instruction address: 0xc0110ddc
> Oops: Kernel access of bad area, sig: 11 [#1]
> Modules linked in:
> NIP: c0110ddc LR: c011118c CTR: 00000000
> REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
> MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
> DAR: 575555f9, DSISR: 40000000
> TASK = cf01c000[1] 'swapper' THREAD: cf01a000
> GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000 c01d0000
> GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00 007fff00
> GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000 00800000
> GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300 57555541
> NIP [c0110ddc] init_dev+0x2bc/0x584
> LR [c011118c] tty_open+0xe8/0x3e0
> Call Trace:
> [cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
> [cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
> [cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
> [cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
> [cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
> [cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
> [cf01bf10] [c00700b4] do_sys_open+0x74/0x114
> [cf01bf40] [c0003c94] init_post+0x34/0x258
> [cf01bf60] [c019ca64] kernel_init+0x258/0x270
> [cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
> Instruction dump:
> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
> ---[ end trace b7795a387aeb7786 ]---
> Kernel panic - not syncing: Attempted to kill init!
> allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.
>
>
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>
>
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-01 16:33 ` Trace Sébastien Chrétien
@ 2008-09-02 0:13 ` Benjamin Herrenschmidt
2008-09-02 5:13 ` Trace Sébastien CHRETIEN
0 siblings, 1 reply; 14+ messages in thread
From: Benjamin Herrenschmidt @ 2008-09-02 0:13 UTC (permalink / raw)
To: Sébastien Chrétien; +Cc: linuxppc-dev, Jenkins, Clive
On Mon, 2008-09-01 at 18:33 +0200, Sébastien Chrétien wrote:
> Thanks for your answer.
> Your analyse of ttys is very well. It was not my answer. All adresses in
> system.map begin with 0xc... So I think it is the case for ttys too.
>
> I found the mistake. It came from my board_device function in struct
> console(console ->device). It didn't change the value of the parameter
> int* index.
> So Linux loaded a tty_structure which was in tiny_ttys[-1]
>
> console.h is not very well documented about this.
You have a custom serial port ? Why not use the framework in
drivers/serial ? Or are you using it ?
Cheers,
Ben.
> Thanks
> Sébastien Chrétien
>
> Jenkins, Clive a écrit :
> >> Why can't tty have value 0x57555541 ?
> >>
> > To answer my own question, because it ends in 1 and is not word-aligned!
> >
> > -----Original Message-----
> > From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org] On Behalf Of Jenkins, Clive
> > Sent: 01 September 2008 14:54
> > To: Sébastien Chrétien
> > Cc: linuxppc-dev@ozlabs.org
> > Subject: RE: Trace
> >
> > I'm not sure that is a failure. Why can't tty have value 0x57555541 ?
> >
> > I think the code in tty_io.c initialises driver->ttys and you shouldn't need to do anything in your driver.
> >
> > If you are not already aware, a useful way to explore kernel code is to use LXR:
> > http://lxr.linux.no/linux+v2.6.26/include/linux/tty_driver.h#L212
> > This may help you understand the tty code.
> >
> > Good luck!
> >
> > ________________________________
> >
> > From: Sébastien Chrétien [mailto:sebastien.chretien.enseirb@gmail.com]
> > Sent: 01 September 2008 13:25
> > To: Jenkins, Clive
> > Cc: linuxppc-dev@ozlabs.org
> > Subject: Re: Trace
> >
> >
> > I found where is the failure with your advices
> > In init_dev (tty_io.c), init_dev calls "tty = driver->ttys[idx]"
> > after this call, tty value is : tty = 0x57555541
> >
> > Have I to initialize driver->ttys in my driver. If yes, how have I to Initialize this ?
> >
> > The driver tty is used in order to have a console on my serial port.
> > Thanks for your help
> >
> >
> >
> > 2008/9/1, Jenkins, Clive <Clive.Jenkins@xerox.com>:
> >
> > The instruction that caused the fault is at this address:
> >
> > > NIP [c0110ddc] init_dev+0x2bc/0x584
> >
> >
> > The hex value of the instruction is also highlighted between <> here:
> >
> > > Instruction dump:
> > > 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
> > > 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
> >
> >
> > Disassemble your kernel and look at offset 0x2BC relative to the label init_dev
> >
> > ________________________________
> >
> > From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:linuxppc-dev-bounces+clive.jenkins <mailto:linuxppc-dev-bounces%2Bclive.jenkins> =xerox.com@ozlabs.org] On Behalf Of Sébastien Chrétien
> > Sent: 01 September 2008 10:16
> > To: linuxppc-dev@ozlabs.org
> > Subject: Trace
> >
> >
> >
> > Hello,
> >
> > I am triying to write a tty_driver under ppc. And I get a kernel panic.
> > Can somebody explain me how finding the source of the error with a kernel panic trace :
> > thanks
> >
> > Unable to handle kernel paging request for data at address 0x575555f9
> > Faulting instruction address: 0xc0110ddc
> > Oops: Kernel access of bad area, sig: 11 [#1]
> > Modules linked in:
> > NIP: c0110ddc LR: c011118c CTR: 00000000
> > REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
> > MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
> > DAR: 575555f9, DSISR: 40000000
> > TASK = cf01c000[1] 'swapper' THREAD: cf01a000
> > GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000 c01d0000
> > GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00 007fff00
> > GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000 00800000
> > GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300 57555541
> > NIP [c0110ddc] init_dev+0x2bc/0x584
> > LR [c011118c] tty_open+0xe8/0x3e0
> > Call Trace:
> > [cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
> > [cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
> > [cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
> > [cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
> > [cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
> > [cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
> > [cf01bf10] [c00700b4] do_sys_open+0x74/0x114
> > [cf01bf40] [c0003c94] init_post+0x34/0x258
> > [cf01bf60] [c019ca64] kernel_init+0x258/0x270
> > [cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
> > Instruction dump:
> > 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
> > 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
> > ---[ end trace b7795a387aeb7786 ]---
> > Kernel panic - not syncing: Attempted to kill init!
> > allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.
> >
> >
> >
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > Linuxppc-dev@ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc-dev
> >
> >
> >
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-02 0:13 ` Trace Benjamin Herrenschmidt
@ 2008-09-02 5:13 ` Sébastien CHRETIEN
2008-09-02 5:45 ` Trace Benjamin Herrenschmidt
0 siblings, 1 reply; 14+ messages in thread
From: Sébastien CHRETIEN @ 2008-09-02 5:13 UTC (permalink / raw)
To: benh; +Cc: linuxppc-dev, Sébastien Chrétien, Jenkins, Clive
My board has only a uart device on a FPGA. I don't use the serial layer
because it isn't documented in Linux Device Driver 3rd. Only the tty
layer is documented
Benjamin Herrenschmidt a écrit :
> On Mon, 2008-09-01 at 18:33 +0200, Sébastien Chrétien wrote:
>
>> Thanks for your answer.
>> Your analyse of ttys is very well. It was not my answer. All adresses in
>> system.map begin with 0xc... So I think it is the case for ttys too.
>>
>> I found the mistake. It came from my board_device function in struct
>> console(console ->device). It didn't change the value of the parameter
>> int* index.
>> So Linux loaded a tty_structure which was in tiny_ttys[-1]
>>
>> console.h is not very well documented about this.
>>
>
> You have a custom serial port ? Why not use the framework in
> drivers/serial ? Or are you using it ?
>
> Cheers,
> Ben.
>
>
>> Thanks
>> Sébastien Chrétien
>>
>> Jenkins, Clive a écrit :
>>
>>>> Why can't tty have value 0x57555541 ?
>>>>
>>>>
>>> To answer my own question, because it ends in 1 and is not word-aligned!
>>>
>>> -----Original Message-----
>>> From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org] On Behalf Of Jenkins, Clive
>>> Sent: 01 September 2008 14:54
>>> To: Sébastien Chrétien
>>> Cc: linuxppc-dev@ozlabs.org
>>> Subject: RE: Trace
>>>
>>> I'm not sure that is a failure. Why can't tty have value 0x57555541 ?
>>>
>>> I think the code in tty_io.c initialises driver->ttys and you shouldn't need to do anything in your driver.
>>>
>>> If you are not already aware, a useful way to explore kernel code is to use LXR:
>>> http://lxr.linux.no/linux+v2.6.26/include/linux/tty_driver.h#L212
>>> This may help you understand the tty code.
>>>
>>> Good luck!
>>>
>>> ________________________________
>>>
>>> From: Sébastien Chrétien [mailto:sebastien.chretien.enseirb@gmail.com]
>>> Sent: 01 September 2008 13:25
>>> To: Jenkins, Clive
>>> Cc: linuxppc-dev@ozlabs.org
>>> Subject: Re: Trace
>>>
>>>
>>> I found where is the failure with your advices
>>> In init_dev (tty_io.c), init_dev calls "tty = driver->ttys[idx]"
>>> after this call, tty value is : tty = 0x57555541
>>>
>>> Have I to initialize driver->ttys in my driver. If yes, how have I to Initialize this ?
>>>
>>> The driver tty is used in order to have a console on my serial port.
>>> Thanks for your help
>>>
>>>
>>>
>>> 2008/9/1, Jenkins, Clive <Clive.Jenkins@xerox.com>:
>>>
>>> The instruction that caused the fault is at this address:
>>>
>>> > NIP [c0110ddc] init_dev+0x2bc/0x584
>>>
>>>
>>> The hex value of the instruction is also highlighted between <> here:
>>>
>>> > Instruction dump:
>>> > 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
>>> > 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
>>>
>>>
>>> Disassemble your kernel and look at offset 0x2BC relative to the label init_dev
>>>
>>> ________________________________
>>>
>>> From: linuxppc-dev-bounces+clive.jenkins=xerox.com@ozlabs.org [mailto:linuxppc-dev-bounces+clive.jenkins <mailto:linuxppc-dev-bounces%2Bclive.jenkins> =xerox.com@ozlabs.org] On Behalf Of Sébastien Chrétien
>>> Sent: 01 September 2008 10:16
>>> To: linuxppc-dev@ozlabs.org
>>> Subject: Trace
>>>
>>>
>>>
>>> Hello,
>>>
>>> I am triying to write a tty_driver under ppc. And I get a kernel panic.
>>> Can somebody explain me how finding the source of the error with a kernel panic trace :
>>> thanks
>>>
>>> Unable to handle kernel paging request for data at address 0x575555f9
>>> Faulting instruction address: 0xc0110ddc
>>> Oops: Kernel access of bad area, sig: 11 [#1]
>>> Modules linked in:
>>> NIP: c0110ddc LR: c011118c CTR: 00000000
>>> REGS: cf01bcb0 TRAP: 0300 Not tainted (2.6.26)
>>> MSR: 00009032 <EE,ME,IR,DR> CR: 44002022 XER: 20000000
>>> DAR: 575555f9, DSISR: 40000000
>>> TASK = cf01c000[1] 'swapper' THREAD: cf01a000
>>> GPR00: 0000000c cf01bd60 cf01c000 cf04c300 ffffffff cf01bdbc 00000000 c01d0000
>>> GPR08: 00001249 fffffffc 00000000 cf000420 84002022 00000000 10000b00 007fff00
>>> GPR16: 0fffa1d0 00000000 00000004 cf01bdbc 007ffec0 00000000 00000000 00800000
>>> GPR24: 00000000 c01b7650 00000002 c01d0000 ffffffff ce4a6700 cf04c300 57555541
>>> NIP [c0110ddc] init_dev+0x2bc/0x584
>>> LR [c011118c] tty_open+0xe8/0x3e0
>>> Call Trace:
>>> [cf01bd60] [cf01bd78] 0xcf01bd78 (unreliable)
>>> [cf01bdb0] [c011118c] tty_open+0xe8/0x3e0
>>> [cf01bde0] [c00742c8] chrdev_open+0x114/0x1b0
>>> [cf01be10] [c006fb5c] __dentry_open+0x190/0x2e8
>>> [cf01be40] [c006fdac] nameidata_to_filp+0x38/0x70
>>> [cf01be60] [c007bc60] do_filp_open+0x200/0x7d0
>>> [cf01bf10] [c00700b4] do_sys_open+0x74/0x114
>>> [cf01bf40] [c0003c94] init_post+0x34/0x258
>>> [cf01bf60] [c019ca64] kernel_init+0x258/0x270
>>> [cf01bff0] [c0011b3c] kernel_thread+0x44/0x60
>>> Instruction dump:
>>> 7d808120 4e800020 7c832378 4bfa9ea9 7c7f1b79 418201f0 a81e0062 2f800001
>>> 409efd98 83ff00d0 2c1f0000 4182fd90 <801f00b8> 70090080 408201b0 801e0060
>>> ---[ end trace b7795a387aeb7786 ]---
>>> Kernel panic - not syncing: Attempted to kill init!
>>> allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Linuxppc-dev mailing list
>>> Linuxppc-dev@ozlabs.org
>>> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>>>
>>>
>>>
>>>
>> _______________________________________________
>> Linuxppc-dev mailing list
>> Linuxppc-dev@ozlabs.org
>> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>>
>
>
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-02 5:13 ` Trace Sébastien CHRETIEN
@ 2008-09-02 5:45 ` Benjamin Herrenschmidt
2008-09-02 7:34 ` Trace Sébastien Chrétien
0 siblings, 1 reply; 14+ messages in thread
From: Benjamin Herrenschmidt @ 2008-09-02 5:45 UTC (permalink / raw)
To: Sébastien CHRETIEN
Cc: linuxppc-dev, Sébastien Chrétien, Jenkins, Clive
On Tue, 2008-09-02 at 07:13 +0200, Sébastien CHRETIEN wrote:
> My board has only a uart device on a FPGA. I don't use the serial layer
> because it isn't documented in Linux Device Driver 3rd. Only the tty
> layer is documented
You won't go very far in linux kernel dev. with using books like
that :-)
Look at other drivers in drivers/serial that should give you all the
information you need :-0
Cheers,
Ben.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-02 5:45 ` Trace Benjamin Herrenschmidt
@ 2008-09-02 7:34 ` Sébastien Chrétien
2008-09-02 8:19 ` Trace Benjamin Herrenschmidt
0 siblings, 1 reply; 14+ messages in thread
From: Sébastien Chrétien @ 2008-09-02 7:34 UTC (permalink / raw)
To: benh; +Cc: Sébastien CHRETIEN, linuxppc-dev, Jenkins, Clive
[-- Attachment #1: Type: text/plain, Size: 577 bytes --]
ok is it a bad way to write a tty driver ? why ?
2008/9/2, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>
> On Tue, 2008-09-02 at 07:13 +0200, Sébastien CHRETIEN wrote:
> > My board has only a uart device on a FPGA. I don't use the serial layer
> > because it isn't documented in Linux Device Driver 3rd. Only the tty
> > layer is documented
>
>
> You won't go very far in linux kernel dev. with using books like
> that :-)
>
> Look at other drivers in drivers/serial that should give you all the
> information you need :-0
>
> Cheers,
> Ben.
>
>
>
[-- Attachment #2: Type: text/html, Size: 865 bytes --]
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-02 7:34 ` Trace Sébastien Chrétien
@ 2008-09-02 8:19 ` Benjamin Herrenschmidt
2008-09-02 8:44 ` Trace Sébastien Chrétien
2008-09-04 20:19 ` Trace Sébastien Chrétien
0 siblings, 2 replies; 14+ messages in thread
From: Benjamin Herrenschmidt @ 2008-09-02 8:19 UTC (permalink / raw)
To: Sébastien Chrétien
Cc: Sébastien CHRETIEN, linuxppc-dev, Jenkins, Clive
On Tue, 2008-09-02 at 09:34 +0200, Sébastien Chrétien wrote:
> ok is it a bad way to write a tty driver ? why ?
Not necessarily, it's just overkill. The UART layer handles a lot
of stuff for you. The tty layer is tricky to get right.
Cheers,
Ben.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-02 8:19 ` Trace Benjamin Herrenschmidt
@ 2008-09-02 8:44 ` Sébastien Chrétien
2008-09-04 20:19 ` Trace Sébastien Chrétien
1 sibling, 0 replies; 14+ messages in thread
From: Sébastien Chrétien @ 2008-09-02 8:44 UTC (permalink / raw)
To: benh; +Cc: linuxppc-dev
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ok. I will try the serial layer
2008/9/2, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>
> On Tue, 2008-09-02 at 09:34 +0200, Sébastien Chrétien wrote:
> > ok is it a bad way to write a tty driver ? why ?
>
>
> Not necessarily, it's just overkill. The UART layer handles a lot
> of stuff for you. The tty layer is tricky to get right.
>
> Cheers,
> Ben.
>
>
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Trace
2008-09-02 8:19 ` Trace Benjamin Herrenschmidt
2008-09-02 8:44 ` Trace Sébastien Chrétien
@ 2008-09-04 20:19 ` Sébastien Chrétien
1 sibling, 0 replies; 14+ messages in thread
From: Sébastien Chrétien @ 2008-09-04 20:19 UTC (permalink / raw)
To: benh; +Cc: Sébastien Chrétien, Jenkins, Clive, linuxppc-dev, EN
I followed your advice : I used the UART layer.
It is easier.
Thanks
Benjamin Herrenschmidt a écrit :
> On Tue, 2008-09-02 at 09:34 +0200, Sébastien Chrétien wrote:
>
>> ok is it a bad way to write a tty driver ? why ?
>>
>
> Not necessarily, it's just overkill. The UART layer handles a lot
> of stuff for you. The tty layer is tricky to get right.
>
> Cheers,
> Ben.
>
>
>
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2008-09-04 20:20 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-09-01 9:16 Trace Sébastien Chrétien
2008-09-01 9:23 ` Trace Benjamin Herrenschmidt
2008-09-01 10:00 ` Trace Jenkins, Clive
2008-09-01 12:25 ` Trace Sébastien Chrétien
2008-09-01 13:54 ` Trace Jenkins, Clive
2008-09-01 13:58 ` Trace Jenkins, Clive
2008-09-01 16:33 ` Trace Sébastien Chrétien
2008-09-02 0:13 ` Trace Benjamin Herrenschmidt
2008-09-02 5:13 ` Trace Sébastien CHRETIEN
2008-09-02 5:45 ` Trace Benjamin Herrenschmidt
2008-09-02 7:34 ` Trace Sébastien Chrétien
2008-09-02 8:19 ` Trace Benjamin Herrenschmidt
2008-09-02 8:44 ` Trace Sébastien Chrétien
2008-09-04 20:19 ` Trace Sébastien Chrétien
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