[PATCH 4/7] Celleb: New HTAB Guest OS Interface on Beat

2007-09-27 Thread Ishizaki Kou
This is a patch kit to work with new Guest OS Interface to tweak HTAB on Beat. It detects old and new Guest OS Interfaces automatically. Signed-off-by: Kou Ishizaki [EMAIL PROTECTED] --- Index: linux-powerpc-git/arch/powerpc/platforms/celleb/setup.c

[PATCH 5/7] Celleb: Supports VFD on Celleb 2

2007-09-27 Thread Ishizaki Kou
This is a patch to support VFD on Celleb 2. VFD is a small LCD to show miscellaneous messages. Signed-off-by: Kou Ishizaki [EMAIL PROTECTED] --- Index: linux-powerpc-git/arch/powerpc/platforms/celleb/Kconfig === ---

Re: [PATCH 1/7] PowerPC64: Not to insert EA=0 entry at

2007-09-27 Thread kou . ishizaki
initializing SLB In-Reply-To: [EMAIL PROTECTED] From: Ishizaki Kou [EMAIL PROTECTED] X-Mailer: Mew version 4.2 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit On Wednesday 26 September 2007, Ishizaki Kou wrote: This

Re: [PATCH 1/7] PowerPC64: Not to insert EA=0 entry at

2007-09-27 Thread Benjamin Herrenschmidt
On Thu, 2007-09-27 at 17:01 +0900, [EMAIL PROTECTED] wrote: Celleb does not set get_paca()-kstack properly (I don't know which function should set it up), so we need to workaround. paca-kstack is set in asm (via the PACAKSAVE macro), from either __secondary_start for non-boot CPUs or from

Re: [PATCH 7/7] Celleb: update for PCI

2007-09-27 Thread Benjamin Herrenschmidt
On Wed, 2007-09-26 at 14:09 +0200, Arnd Bergmann wrote: Is there a way that we can make that code common? I guess there could be a file in arch/powerpc/sysdev that can handle this correctly for all hardware that requires this particular workaround (currently celleb and QS20, but potentially

Re: [PATCH 2/7] Celleb: Move pause, kexec_cpu_down to beat.c

2007-09-27 Thread Ishizaki Kou
On Wednesday 26 September 2007, Ishizaki Kou wrote: This patch is an update for Beat on Celleb - Move beat_pause(), beat_kexec_cpu_down() from setup.c to beat.c =20 Signed-off-by: [EMAIL PROTECTED] =20 Acked-by: Arnd Bergmann [EMAIL PROTECTED] =20 The patch looks good, once you fix

Re: [PATCH 4/7] Celleb: New HTAB Guest OS Interface on Beat

2007-09-27 Thread Benjamin Herrenschmidt
On Thu, 2007-09-27 at 16:53 +0900, Ishizaki Kou wrote: This is a patch kit to work with new Guest OS Interface to tweak HTAB on Beat. It detects old and new Guest OS Interfaces automatically. You may also consider adding an API to Beat to invalidate ranges of addresses. We could us that

Re: [PATCH 4/7] Celleb: New HTAB Guest OS Interface on Beat

2007-09-27 Thread Arnd Bergmann
On Thursday 27 September 2007, Ishizaki Kou wrote: This is a patch kit to work with new Guest OS Interface to tweak HTAB on Beat. It detects old and new Guest OS Interfaces automatically. Signed-off-by: Kou Ishizaki [EMAIL PROTECTED] Acked-by: Arnd Bergmann [EMAIL PROTECTED] The code looks

Re: [PATCH 5/7] Celleb: Supports VFD on Celleb 2

2007-09-27 Thread Arnd Bergmann
On Thursday 27 September 2007, Ishizaki Kou wrote: This is a patch to support VFD on Celleb 2. VFD is a small LCD to show miscellaneous messages. Signed-off-by: Kou Ishizaki [EMAIL PROTECTED] The implementation looks fine, but I'm not sure if /proc/ppc64/rtas is the right way to do it. The

Linux 2.6.22 Serial Core

2007-09-27 Thread Deepak Gaur
Hi all, Just a small question! The serial core driver file located in drivers/serial directory (drivers/serial/serial_core.c) does not have module_init() and module_exit() function called though CONFIG_SERIAL_CORE flag is seperately defined in Kconfig and is used in makefile. Any idea why

Re: [PATCH] add Altivec/VMX state to coredumps

2007-09-27 Thread Kumar Gala
You're probably right :) What cores have SPE at the moment? Also, perhaps more importantly, are there any plans to have Altivec and SPE in the same core? The e500 cores's from Freescale. No, they are pretty much mutually exclusive. I've been working with Carlos Eduardo Seo (Cc'ed on this

Re: [PATCH 1/7] PowerPC64: Not to insert EA=0 entry at

2007-09-27 Thread Ishizaki Kou
Ben-san, On Thu, 2007-09-27 at 17:01 +0900, [EMAIL PROTECTED] wrote: Celleb does not set get_paca()-kstack properly (I don't know which function should set it up), so we need to workaround. paca-kstack is set in asm (via the PACAKSAVE macro), from either __secondary_start for non-boot

Re: [PATCH 3/5] ibmebus: Add device creation and bus probing based on of_device

2007-09-27 Thread Arnd Bergmann
On Wednesday 26 September 2007, Joachim Fenkes wrote: The devtree root is now searched for devices matching a built-in whitelist during boot, so these devices appear on the bus from the beginning. It is still possible to manually add/remove devices to/from the bus by using the probe/remove

Re: [PATCH 1/5] PowerPC: Move of_device allocation into of_device.[ch]

2007-09-27 Thread Arnd Bergmann
On Wednesday 26 September 2007, Joachim Fenkes wrote: Extract generic of_device allocation code from of_platform_device_create() and move it into of_device.[ch], called of_device_alloc(). Also, there's now of_device_free() which puts the device node. This way, bus drivers that build on

Re: [PATCH 4/5] ibmebus: Move to of_device and of_platform_driver, match eHCA and eHEA drivers

2007-09-27 Thread Arnd Bergmann
On Wednesday 26 September 2007, Joachim Fenkes wrote: Replace struct ibmebus_dev and struct ibmebus_driver with struct of_device and struct of_platform_driver, respectively. Match the external ibmebus interface and drivers using it. Signed-off-by: Joachim Fenkes [EMAIL PROTECTED] Acked-by:

Re: [PATCH 2/5] ibmebus: Remove bus match/probe/remove functions

2007-09-27 Thread Arnd Bergmann
On Wednesday 26 September 2007, Joachim Fenkes wrote: Remove old code that will be replaced by rewritten and shorter functions in the next patch. Keep struct ibmebus_dev and struct ibmebus_driver for now, but replace ibmebus_{,un}register_driver() by dummy functions. This way, the kernel will

Re: [Cbe-oss-dev] [patch 0/8] PS3 AV Settings Driver patches for 2.6.24

2007-09-27 Thread Geert Uytterhoeven
On Thu, 27 Sep 2007, Michael Ellerman wrote: On Wed, 2007-09-26 at 18:33 +0200, Geert Uytterhoeven wrote: Here are some new patches for the PS3 AV Settings Driver (ps3av), which is used in close collaboration with the PS3 Virtual Frame Buffer Device Driver (ps3fb): [1] ps3av: eliminate

Re: dtc: Use libfdt/fdt.h instead of flat_dt.h

2007-09-27 Thread Jon Loeliger
So, like, the other day David Gibson mumbled: In the dtc tree, both flat_dt.h and libfdt/fdt.h have structures and constants relating to the flattened device tree format derived from asm-powerpc/prom.h in the kernel. The former is used in dtc, the latter in libfdt. libfdt/fdt.h is the more

Re: Help! Debian ppc64

2007-09-27 Thread Olof Johansson
Hi, On Thu, Sep 27, 2007 at 09:57:02AM -0400, Cesar Bello wrote: Hi, I'm writing from Venezuela. I have to prepair a presentation about Debian on IBM pSerires Servers with Power 5+ processors. My first question is what are the advantages of use Debian GNU/Linux on pSeries Servers? Sounds like

Re: Help! Debian ppc64

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 09:57:02AM -0400, Cesar Bello wrote: Hi, I'm writing from Venezuela. I have to prepair a presentation about Debian on IBM pSerires Servers with Power 5+ processors. My first question is what are the advantages of use Debian GNU/Linux on pSeries Servers? Advantages as

Re: [PATCH 8/15] bootwrapper: convert flatdevtree to version 16

2007-09-27 Thread Milton Miller
On Sep 26, 2007, at 9:45 PM, David Gibson wrote: On Wed, Sep 26, 2007 at 11:19:47AM -0500, Milton Miller wrote: On Sep 24, 2007, at 10:46 PM, David Gibson wrote: On Mon, Sep 24, 2007 at 01:54:32AM -0500, Milton Miller wrote: On Sep 23, 2007, at 10:36 PM, David Gibson wrote: On Fri, Sep 21,

Re: [PATCH 5/7] Celleb: Supports VFD on Celleb 2

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 11:07:33AM +0200, Arnd Bergmann wrote: On Thursday 27 September 2007, Ishizaki Kou wrote: This is a patch to support VFD on Celleb 2. VFD is a small LCD to show miscellaneous messages. Signed-off-by: Kou Ishizaki [EMAIL PROTECTED] My feeling is that your

Re: [Cbe-oss-dev] [patch 0/8] PS3 AV Settings Driver patches for 2.6.24

2007-09-27 Thread Geoff Levand
Michael Ellerman wrote: On Wed, 2007-09-26 at 18:33 +0200, Geert Uytterhoeven wrote: Hi, Here are some new patches for the PS3 AV Settings Driver (ps3av), which is used in close collaboration with the PS3 Virtual Frame Buffer Device Driver (ps3fb): [1] ps3av: eliminate unneeded

Re: tg3: PCI error recovery

2007-09-27 Thread Linas Vepstas
During a private conversation about how to save and restore device state after a pci error is detected, and the device is reset, the following came up: On Wed, Sep 26, 2007 at 04:48:38PM -0700, Michael Chan wrote: 1b) If so, is it safe to call pci_save_state() in

[PATCH v3] Make instruction dumping work in real mode.

2007-09-27 Thread Scott Wood
On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of the IMMU, and if necessary converts PC into a virtual address.

Re: [PATCH v3] Make instruction dumping work in real mode.

2007-09-27 Thread Kumar Gala
On Sep 27, 2007, at 1:00 PM, Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of the

Re: [PATCH v3] Make instruction dumping work in real mode.

2007-09-27 Thread Sergei Shtylyov
Hello. Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of the IMMU, and if necessary

Re: [PATCH v3] Make instruction dumping work in real mode.

2007-09-27 Thread Grant Likely
On 9/27/07, Sergei Shtylyov [EMAIL PROTECTED] wrote: Hello. Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This

[PATCH v4] Make instruction dumping work in real mode.

2007-09-27 Thread Scott Wood
On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of the IMMU, and if necessary converts PC into a virtual address.

Re: [PATCH v4] Make instruction dumping work in real mode.

2007-09-27 Thread Olof Johansson
On Thu, Sep 27, 2007 at 01:38:55PM -0500, Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of

Re: [PATCH v4] Make instruction dumping work in real mode.

2007-09-27 Thread Kumar Gala
On Sep 27, 2007, at 1:38 PM, Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of the

Re: jffs2 file system on MPC8272ADS board

2007-09-27 Thread Vitaly Bordug
Hello Nethra, On Wed, 26 Sep 2007 05:34:14 -0700 (PDT) Nethra wrote: Hello , hi everyone, I m using custom board similar to MPC8272ADS board... 1) For the first time it boots up properly in case if we overwrite any existing binaries using nfs mounted file system on the

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 09:12:33PM +0200, Gerhard Pircher wrote: Hi, I'm working on a 2.6.23 kernel for the AmigaOne. [...] 6PCI: Probing PCI hardware. 7PCI: Scanning bus 0... ...00:00:07.0. 7PCI: Calling quirk... ...CI: Found :00:07.2 [1106/303... Any chance that this thing has

2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Gerhard Pircher
Hi, I'm working on a 2.6.23 kernel for the AmigaOne. I implemented the device tree and the platform setup code, which all compiles fine. I built a cuImage target, loaded it on my target machine with TFTP and booted it. The kernel passes the platform setup code and then dies somewhere in the

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Gerhard Pircher
Original-Nachricht Datum: Thu, 27 Sep 2007 14:25:51 -0500 Von: [EMAIL PROTECTED] An: Gerhard Pircher [EMAIL PROTECTED] CC: linuxppc-dev@ozlabs.org Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? On Thu, Sep 27, 2007 at 09:12:33PM +0200, Gerhard Pircher wrote: Hi,

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 09:31:31PM +0200, Gerhard Pircher wrote: Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? I'm working on a 2.6.23 kernel for the AmigaOne. Have you tried 2.6.22, or does that fail also? --linas ___ Linuxppc-dev

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Gerhard Pircher
Original-Nachricht Datum: Thu, 27 Sep 2007 15:50:12 -0500 Von: [EMAIL PROTECTED] An: Gerhard Pircher [EMAIL PROTECTED] CC: linuxppc-dev@ozlabs.org Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? On Thu, Sep 27, 2007 at 09:31:31PM +0200, Gerhard Pircher wrote:

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 11:17:00PM +0200, Gerhard Pircher wrote: Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? Do you have an idea how to debug it? Not particularly. What caught my eye was the failure right near the PCI quirk stuff, as I was having problems there as well (but

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Gerhard Pircher
Original-Nachricht Datum: Thu, 27 Sep 2007 16:35:03 -0500 Von: [EMAIL PROTECTED] An: Gerhard Pircher [EMAIL PROTECTED] CC: linuxppc-dev@ozlabs.org Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? On Thu, Sep 27, 2007 at 11:17:00PM +0200, Gerhard Pircher wrote:

Re: [PATCH 1/7] PowerPC64: Not to insert EA=0 entry at

2007-09-27 Thread Benjamin Herrenschmidt
On Thu, 2007-09-27 at 20:22 +0900, Ishizaki Kou wrote: Ben-san, On Thu, 2007-09-27 at 17:01 +0900, [EMAIL PROTECTED] wrote: Celleb does not set get_paca()-kstack properly (I don't know which function should set it up), so we need to workaround. paca-kstack is set in asm (via the

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Gerhard Pircher
Original-Nachricht Datum: Thu, 27 Sep 2007 17:20:07 -0500 Von: [EMAIL PROTECTED] An: Gerhard Pircher [EMAIL PROTECTED] CC: linuxppc-dev@ozlabs.org Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? On Thu, Sep 27, 2007 at 11:57:35PM +0200, Gerhard Pircher wrote: The

Re: [PATCH 2/2]: PCI Error Recovery: Symbios SCSI First Failure

2007-09-27 Thread Linas Vepstas
On Wed, Sep 26, 2007 at 09:02:16AM -0600, Matthew Wilcox wrote: On Fri, Apr 20, 2007 at 03:47:20PM -0500, Linas Vepstas wrote: Implement the so-called first failure data capture (FFDC) for the symbios PCI error recovery. After a PCI error event is reported, the driver requests that MMIO be

Re: [PATCH 2/2]: PCI Error Recovery: Symbios SCSI First Failure

2007-09-27 Thread Matthew Wilcox
On Thu, Sep 27, 2007 at 05:00:22PM -0500, Linas Vepstas wrote: On Wed, Sep 26, 2007 at 09:02:16AM -0600, Matthew Wilcox wrote: I'm a little concerned by the mention of MMIO. It's entirely possible for the sym2 driver to be using ioports to access the card rather than MMIO. Is it simply

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 11:57:35PM +0200, Gerhard Pircher wrote: Based on your boot messages, it looks like you are failing somewhere in pci probe. My olde-fashioned, slow, but-usually-works method is to sprinkle enough printk's into the code to catch it in the act. I guess the code in

Re: [PATCH 1/7] PowerPC64: Not to insert EA=0 entry at

2007-09-27 Thread Benjamin Herrenschmidt
It should have been set in setup_64.c, in setup_paca() (which is called twice) in that statement: local_paca = paca[cpu]; As local_paca is defined as being a variable held in register r13. Maybe something bad's happening with the compiler ? Can you check early_setup disassembly,

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Benjamin Herrenschmidt
On Fri, 2007-09-28 at 00:27 +0200, Gerhard Pircher wrote: Original-Nachricht Datum: Thu, 27 Sep 2007 17:20:07 -0500 Von: [EMAIL PROTECTED] An: Gerhard Pircher [EMAIL PROTECTED] CC: linuxppc-dev@ozlabs.org Betreff: Re: 2.6.23-rc8 dies somewhere during boot!? On

Re: 2.6.23-rc8 dies somewhere during boot!?

2007-09-27 Thread Paul Mackerras
Gerhard Pircher writes: I'm working on a 2.6.23 kernel for the AmigaOne. I implemented the device tree and the platform setup code, which all compiles fine. I built a cuImage target, loaded it on my target machine with TFTP and booted it. The kernel passes the platform setup code and then

Re: [PATCH v4] Make instruction dumping work in real mode.

2007-09-27 Thread Scott Wood
Michael Ellerman wrote: On Thu, 2007-09-27 at 13:38 -0500, Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch

Re: jffs2 file system on MPC8272ADS board

2007-09-27 Thread Detlev Zundel
Hi Nethra, The other options I am wondering about, -c, --cleanmarker=SIZE Size of cleanmarker (default 12) -n, --no-cleanmarkers Don't add a cleanmarker to every eraseblock cleanmaker size will it help the cause? Skimming through the thread I cannot tell whether you use NAND or NOR, but

Re: [PATCH v4] Make instruction dumping work in real mode.

2007-09-27 Thread Michael Ellerman
On Thu, 2007-09-27 at 13:38 -0500, Scott Wood wrote: On non-book-E-or-4xx, exceptions execute in real mode. If a fault happens that leads to a register dump, the kernel currently prints because it doesn't realize that PC is a physical address. This patch checks the state of the

Re: [PATCH 2/2]: PCI Error Recovery: Symbios SCSI First Failure

2007-09-27 Thread Linas Vepstas
On Thu, Sep 27, 2007 at 04:10:31PM -0600, Matthew Wilcox wrote: In the error handler, we wait_for_completion(io_reset_wait). In sym2_io_error_detected, we init_completion(io_reset_wait). Isn't it possible that we hit the error handler before we hit the io_error_detected path, and thus the

Re: dtc: Use libfdt/fdt.h instead of flat_dt.h

2007-09-27 Thread David Gibson
On Thu, Sep 27, 2007 at 08:26:14AM -0500, Jon Loeliger wrote: So, like, the other day David Gibson mumbled: In the dtc tree, both flat_dt.h and libfdt/fdt.h have structures and constants relating to the flattened device tree format derived from asm-powerpc/prom.h in the kernel. The former

Re: [PATCH] add Altivec/VMX state to coredumps

2007-09-27 Thread Michael Ellerman
On Thu, 2007-09-27 at 05:10 -0500, Kumar Gala wrote: You're probably right :) What cores have SPE at the moment? Also, perhaps more importantly, are there any plans to have Altivec and SPE in the same core? The e500 cores's from Freescale. No, they are pretty much mutually

Re: [PATCH 8/15] bootwrapper: convert flatdevtree to version 16

2007-09-27 Thread David Gibson
On Thu, Sep 27, 2007 at 10:44:27AM -0500, Milton Miller wrote: On Sep 26, 2007, at 9:45 PM, David Gibson wrote: [snip] What's your souce for saying the were supposed to be backwards compatable? That dtc fills out the struct header so? Sitting next to BenH and knowing he always intended

Re: [patch 3/3] mpc8349emitx.dts: Add ds1339 RTC

2007-09-27 Thread David Gibson
On Tue, Sep 25, 2007 at 10:33:58PM +0200, Segher Boessenkool wrote: Hrm... we probably want an i2c device_type class, but I don't think we've actually defined one, which is a problem By defining new device_type's, or new semantics for device_type, you open the door to (accidentally)

libfdt: libfdt_env.h must be included first

2007-09-27 Thread David Gibson
libfdt.h currently includes fdt.h, then libfdt_env.h. This is incorrect, because depending on the environment into which libfdt is embedded, libfdt_env.h may be needed to define datatypes used in fdt.h. This patch corrects the problem. Signed-off-by: David Gibson [EMAIL PROTECTED] Index:

libfdt: Test rw functions on more trees

2007-09-27 Thread David Gibson
At present, the testcases for read/write functions (setprop, del_property and del_node) are only invoked on the single asm-generated tree, not on any of the other tree images which should be equivalent. The functions in question will (correctly) not work on the unfinished tree output from

Re: libfdt: libfdt_env.h must be included first

2007-09-27 Thread Stephen Rothwell
On Fri, 28 Sep 2007 14:52:06 +1000 David Gibson [EMAIL PROTECTED] wrote: libfdt.h currently includes fdt.h, then libfdt_env.h. This is incorrect, because depending on the environment into which libfdt is embedded, libfdt_env.h may be needed to define datatypes used in fdt.h. This patch

Re: libfdt: libfdt_env.h must be included first

2007-09-27 Thread David Gibson
On Fri, Sep 28, 2007 at 03:13:22PM +1000, Stephen Rothwell wrote: On Fri, 28 Sep 2007 14:52:06 +1000 David Gibson [EMAIL PROTECTED] wrote: libfdt.h currently includes fdt.h, then libfdt_env.h. This is incorrect, because depending on the environment into which libfdt is embedded,

libfdt: Make unit address optional for finding nodes

2007-09-27 Thread David Gibson
At present, the fdt_subnode_offset() and fdt_path_offset() functions in libfdt require the exact name of the nodes in question be passed, including unit address. This is contrary to traditional OF-like finddevice() behaviour, which allows the unit address to be omitted (which is useful when the