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* Re: 2.5.51 ide module problem
@ 2002-12-11  6:50 Adam J. Richter
  2002-12-11  7:07 ` Jeff Chua
  0 siblings, 1 reply; 13+ messages in thread
From: Adam J. Richter @ 2002-12-11  6:50 UTC (permalink / raw)
  To: jchua; +Cc: linux-kernel

>depmod will ecounter "Segmentation fault" if the ide.ko and ide-io.ps
>modules are in /lib/modules/2.5.51/kernel

	I think the new depmod recurses infinitely when it encounters
circular dependencies.  It eventually segfaults and leaves a huge
modules.dep file from the infinite loop.  If you look at the final
huge line in that file, you can see where the loop occurred.

	depmod has no need to do any recursion, since it only needs
to determine the immediate dependencies of each module.  However,
noticing such loops and printing them out would be a handy feature.

	I use IDE as a module, but I had to change the Makefile to
build a big ide-mod.o from most of the core objects rather than
allowing each one to be its own module.  I believe I posted IDE
modularization patches at least once a couple of months ago, but it
seems to have fallen between the cracks.  I could repost it if need
be, although I have not yet booted 2.5.51.

	Also note that I have not used the in kernel-based module
loader recently, as I have been patching my kernels to use the user
level module code.  I am planning to try the kernel-base module loader
in 2.5.51 once I fix other problems it has finding the root device
under devfs.  So, it's remotely possible that you may also see module
problems that I've missed.

Adam J. Richter     __     ______________   575 Oroville Road
adam@yggdrasil.com     \ /                  Milpitas, California 95035
+1 408 309-6081         | g g d r a s i l   United States of America
                         "Free Software For The Rest Of Us."

^ permalink raw reply	[flat|nested] 13+ messages in thread
* Re: 2.5.51 ide module problem
@ 2002-12-18 14:18 Adam J. Richter
  0 siblings, 0 replies; 13+ messages in thread
From: Adam J. Richter @ 2002-12-18 14:18 UTC (permalink / raw)
  To: alan; +Cc: andre, axboe, linux-kernel


	I forgot to mention one thing in my the message that I sent
a minute ago: I understand that the cmd640_vlb kernel command line
argument needs to be settable via a module parameters for cmd640 to
be fully functional as a kernel module.  I will take care of that
if making cmd640 a module would work in the scenario that I described
(userland is careful not to set 32-bit IO or IRQ unmasking until the
cmd640 module can be loaded).

Adam J. Richter     __     ______________   575 Oroville Road
adam@yggdrasil.com     \ /                  Milpitas, California 95035
+1 408 309-6081         | g g d r a s i l   United States of America
                         "Free Software For The Rest Of Us."

^ permalink raw reply	[flat|nested] 13+ messages in thread
* Re: 2.5.51 ide module problem
@ 2002-12-18 14:14 Adam J. Richter
  2002-12-18 16:07 ` Alan Cox
  0 siblings, 1 reply; 13+ messages in thread
From: Adam J. Richter @ 2002-12-18 14:14 UTC (permalink / raw)
  To: alan; +Cc: andre, axboe, linux-kernel

On 2002-12-13, Alan Cox wrote:
>On Fri, 2002-12-13 at 07:59, Adam J. Richter wrote:

>> --- linux-2.5.51/drivers/pci/pci.c	2002-12-09 18:45:52.000000000 -0800
>> +++ linux/drivers/pci/pci.c	2002-12-09 19:03:18.000000000 -0800
[...]
>> diff -r -u linux-2.5.51/drivers/ide/Kconfig linux/drivers/ide/Kconfig
>> --- linux-2.5.51/drivers/ide/Kconfig	2002-12-09 18:45:56.000000000 -0800
>> +++ linux/drivers/ide/Kconfig	2002-11-27 18:23:46.000000000 -0800
>> @@ -199,7 +199,7 @@
>>  	depends on BLK_DEV_IDE
>>  
>>  config BLK_DEV_CMD640
>> -	bool "CMD640 chipset bugfix/support"
>> +	tristate "CMD640 chipset bugfix/support"

>Please don't do this. You can't "load" the workaround meaningfully for
>this device


	I'd appreciate some clarification on what trouble the generic
IDE driver can get into when the cmd640 code is not present.
linux-2.5.52/Documentation/ide.txt says:

|  For the CMD640, linux disables "IRQ unmasking" (hdparm -u1) on any
|  drive for which the "prefetch" mode of the CMD640 is turned on.
|  If "prefetch" is disabled (hdparm -p8), then "IRQ unmasking" can be
|  used again.
|
|  For the CMD640, linux disables "32bit I/O" (hdparm -c1) on any drive
|  for which the "prefetch" mode of the CMD640 is turned off.
|  If "prefetch" is enabled (hdparm -p9), then "32bit I/O" can be
|  used again.
|
|  The CMD640 is also used on some Vesa Local Bus (VLB) cards, and is *NOT*
|  automatically detected by Linux.  For safe, reliable operation with such
|  interfaces, one *MUST* use the "ide0=cmd640_vlb" kernel option.
|
|  Use of the "serialize" option is no longer necessary.

	As I understand it, both IRQ unmasking and 32 bit I/O are off
by default.  So, while a system could get into trouble by enabling
those options on a cmd640 system before the cmd640 module is loaded,
it sounds like it should be feasible to have IDE initially come up
without the cmd640 workarounds at a stage where the user level code
knows not to enable DMA or 32-bit PIO (for example, a boot floppy or
initial ramdisk), and then later loads the cmd640 workaround and other
PCI drivers (when a directory tree with a wider selection of modules
has been mounted).

	I wouldn't mind submitting the other IDE modularization
changes first sorting out cmd640 modularization later, but doing so
would involve a couple of inelegant Makefile changes that would have
to be reversed if cmd640 could later be a separate module, because it
would inolvolve linking d a .o from a subdirectory to build a module
(ide-probe.o, ide.o, ..., pci/cmd640.o).  So, I'd like to try to
understand now if this is really necessary.

Adam J. Richter     __     ______________   575 Oroville Road
adam@yggdrasil.com     \ /                  Milpitas, California 95035
+1 408 309-6081         | g g d r a s i l   United States of America
                         "Free Software For The Rest Of Us."

`h

^ permalink raw reply	[flat|nested] 13+ messages in thread
* 2.5.51 ide module problem
@ 2002-12-11  5:49 Jeff Chua
  0 siblings, 0 replies; 13+ messages in thread
From: Jeff Chua @ 2002-12-11  5:49 UTC (permalink / raw)
  To: Linux Kernel


My linux/.config ...
CONFIG_IDE=m
CONFIG_BLK_DEV_IDE=m
CONFIG_BLK_DEV_IDEDISK=m
CONFIG_BLK_DEV_IDECS=m
CONFIG_BLK_DEV_IDECD=m
CONFIG_BLK_DEV_IDEFLOPPY=m
CONFIG_BLK_DEV_IDESCSI=m
CONFIG_BLK_DEV_IDE_MODES=y

System version ...
	module-init-tools-0.9.3
	linux-2.5.51

depmod will ecounter "Segmentation fault" if the ide.ko and ide-io.ps
modules are in /lib/modules/2.5.51/kernel

After "rm ide.ko ide-io.ps", depmod runs fine, but that means ide won't
load.

Thanks,
Jeff
[ jchua@fedex.com ]

^ permalink raw reply	[flat|nested] 13+ messages in thread
end of thread, other threads:[~2002-12-18 22:01 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2002-12-11  6:50 2.5.51 ide module problem Adam J. Richter
2002-12-11  7:07 ` Jeff Chua
2002-12-11  8:41   ` Adam J. Richter
     [not found]     ` <Pine.LNX.4.50.0212111711180.4632-200000@boston.corp.fedex.com>
2002-12-13  7:59       ` Adam J. Richter
2002-12-13 10:31         ` Alan Cox
2002-12-14  6:45         ` Jeff Chua
  -- strict thread matches above, loose matches on Subject: below --
2002-12-18 14:18 Adam J. Richter
2002-12-18 14:14 Adam J. Richter
2002-12-18 16:07 ` Alan Cox
2002-12-18 19:50   ` Jeff Chua
2002-12-18 22:43     ` Alan Cox
2002-12-18 22:06       ` Andre Hedrick
2002-12-11  5:49 Jeff Chua

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