Re: RTC problem in PS3

Hi,

Marvin wrote:

forward to a better place...

On Sunday 16 November 2008 23:44:50 Fabiano Manoel de Andrade wrote:

quoted

	Hi I've compiled the latest version of linux kernel (2.6.27.6) in my
PS3 running debian and get a warning message listed here

	Setting the system clock.
  	Cannot access the Hardware Clock via any known method.
  	Use the --debug option to see the details of our search for an access
method. * Unable to set System Clock to: Sun Nov 16 20:33:06 UTC 2008


	The problem can be reproduced with the commands

	# hwclock --debug
 	hwclock from util-linux-ng 2.13.1.1
  	hwclock: Open of /dev/rtc failed, errno=2: No such file or directory.
  	No usable clock interface found.
  	Cannot access the Hardware Clock via any known method.
  	# ls -l /dev/rtc*
  	ls: cannot access /dev/rtc*: No such file or directory

	Loading the rtc-ppc module solve the problem, but after restart
the system I still have the problem. Looking at kernel config I change the
rtc-ppc to be build into kernel and this solve totally the problem. So the
ps3_defconfig must set the rtc-ppc to be build into kernel.

This is do to a bug in the rtc-ppc driver.  It is not PS3 specific, but
will affect all powerpc machines that use the rtc-ppc driver and have it
built as a loadable module.

Normally, udev will automatically load drivers for the devices present in the
system.  The info udev uses to autoload the driver is not provided by the
rtc-ppc driver, so when it is build as a loadable module udev can't figure
out which driver to load.

Here is some discussion Geert and I had:

-------- Original Message --------
On Tue, 2 Dec 2008, Geert Uytterhoeven wrote:

On Mon, 1 Dec 2008, Geoff Levand wrote:

quoted

There is a similar problem when the new generic ppc-rtc driver is
built as a module and the startup scripts try to access the RTC.

Add it to /etc/modules? But then it'll be loaded on all platforms. But as it
uses the ppc_md infrastructure, that may actually be the right thing to do on
all PPC platforms.

However, ppc-rtc looks like a strange driver: it creates a platform_device, but
doesn't contain the corresponding platform_driver.
Ah, it creates the platform_device just to be able to pass a struct device to
rtc_device_register().

But as all of this is done from module_init(), there's no opportunity for
autoloading....

It can be solved...

If the creation of the "ppc-rtc" platform device would be moved to builtin
core code (e.g. arch/powerpc/kernel/setup-common.c?), and drivers/rtc/rtc-ppc.c
would become a real platform driver that binds to the "ppc-rtc" platform
device, then it would be autoloaded by udev.

-Geoff