Re: [PATCH] docs: Update FireWire debugging documentation

From: Stefan Richter
Date: Mon Dec 23 2013 - 10:19:00 EST


CC'ing linux1394-devel, quoting in full.

On Dec 22 Lubomir Rintel wrote:
> The old firewire stack is long dead now and a new version firescope has been
> released with support for current kernels.
>
> Cc: Rob Landley <rob@xxxxxxxxxxx>
> Cc: Justin P. Mattock <justinmattock@xxxxxxxxx>
> Cc: Bernhard Kaindl <bk@xxxxxxx>
> Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>

Reviewed-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>

> ---
> Documentation/debugging-via-ohci1394.txt | 24 +++++++++---------------
> Documentation/power/basic-pm-debugging.txt | 2 +-
> 2 files changed, 10 insertions(+), 16 deletions(-)

Rob, will you be taking this or should it go into linux1394.git?

Lubomir sent another patch for linux1394.git which among else also touches
Documentation/debugging-via-ohci1394.txt, but git's default merge strategy
handles this overlap automatically and correctly. I.e. this can go
separate ways to upstream.
(http://marc.info/?l=linux1394-devel&m=138770970409985,
"[PATCH] ohci: Turn remote DMA support into a module parameter")

> diff --git a/Documentation/debugging-via-ohci1394.txt b/Documentation/debugging-via-ohci1394.txt
> index 611f5a5..14d1944 100644
> --- a/Documentation/debugging-via-ohci1394.txt
> +++ b/Documentation/debugging-via-ohci1394.txt
> @@ -36,17 +36,13 @@ available (notebooks) or too slow for extensive debug information (like ACPI).
> Drivers
> -------
>
> -The ohci1394 driver in drivers/ieee1394 initializes the OHCI-1394 controllers
> -to a working state and enables physical DMA by default for all remote nodes.
> -This can be turned off by ohci1394's module parameter phys_dma=0.
> -
> -The alternative firewire-ohci driver in drivers/firewire uses filtered physical
> +The firewire-ohci driver in drivers/firewire uses filtered physical
> DMA by default, which is more secure but not suitable for remote debugging.
> Compile the driver with CONFIG_FIREWIRE_OHCI_REMOTE_DMA (Kernel hacking menu:
> Remote debugging over FireWire with firewire-ohci) to get unfiltered physical
> DMA.
>
> -Because ohci1394 and firewire-ohci depend on the PCI enumeration to be
> +Because the firewire-ohci driver depends on the PCI enumeration to be
> completed, an initialization routine which runs pretty early has been
> implemented for x86. This routine runs long before console_init() can be
> called, i.e. before the printk buffer appears on the console.
> @@ -64,7 +60,7 @@ be used to view the printk buffer of a remote machine, even with live update.
>
> Bernhard Kaindl enhanced firescope to support accessing 64-bit machines
> from 32-bit firescope and vice versa:
> -- http://halobates.de/firewire/firescope-0.2.2.tar.bz2
> +- http://v3.sk/~lkundrak/firescope/
>
> and he implemented fast system dump (alpha version - read README.txt):
> - http://halobates.de/firewire/firedump-0.1.tar.bz2
> @@ -92,11 +88,11 @@ Step-by-step instructions for using firescope with early OHCI initialization:
>
> 1) Verify that your hardware is supported:
>
> - Load the ohci1394 or the fw-ohci module and check your kernel logs.
> + Load the firewire-ohci module and check your kernel logs.
> You should see a line similar to
>
> - ohci1394: fw-host0: OHCI-1394 1.1 (PCI): IRQ=[18] MMIO=[fe9ff800-fe9fffff]
> - ... Max Packet=[2048] IR/IT contexts=[4/8]
> + firewire_ohci 0000:15:00.1: added OHCI v1.0 device as card 2, 4 IR + 4 IT
> + ... contexts, quirks 0x11
>
> when loading the driver. If you have no supported controller, many PCI,
> CardBus and even some Express cards which are fully compliant to OHCI-1394
> @@ -113,20 +109,18 @@ Step-by-step instructions for using firescope with early OHCI initialization:
>
> If an driver is running on both machines you should see a line like
>
> - ieee1394: Node added: ID:BUS[0-01:1023] GUID[0090270001b84bba]
> + firewire_core 0000:15:00.1: created device fw1: GUID 00061b0020105917, S400
>
> on both machines in the kernel log when the cable is plugged in
> and connects the two machines.
>
> 3) Test physical DMA using firescope:
>
> - On the debug host,
> - - load the raw1394 module,
> - - make sure that /dev/raw1394 is accessible,
> + On the debug host, make sure that /dev/fw* is accessible,
> then start firescope:
>
> $ firescope
> - Port 0 (ohci1394) opened, 2 nodes detected
> + Port 0 (/dev/fw1) opened, 2 nodes detected
>
> FireScope
> ---------
> diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt
> index e9b54de8..edeecd4 100644
> --- a/Documentation/power/basic-pm-debugging.txt
> +++ b/Documentation/power/basic-pm-debugging.txt
> @@ -172,7 +172,7 @@ you can boot the kernel with the 'no_console_suspend' parameter and try to log
> kernel messages using the serial console. This may provide you with some
> information about the reasons of the suspend (resume) failure. Alternatively,
> it may be possible to use a FireWire port for debugging with firescope
> -(ftp://ftp.firstfloor.org/pub/ak/firescope/). On x86 it is also possible to
> +(http://v3.sk/~lkundrak/firescope/). On x86 it is also possible to
> use the PM_TRACE mechanism documented in Documentation/power/s2ram.txt .
>
> 2. Testing suspend to RAM (STR)



--
Stefan Richter
-=====-===-= ==-- =-===
http://arcgraph.de/sr/
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