July 2006 - Darwin-kernel - lists.apple.com

a Kernel hack for a Powerbook thermal sensor gone crazy?
by Fabio Cionini 25 Jul '06

25 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thanks in advance, Fabio Cionini _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Hello to everyone, I have a big issue with my Powerbook G4 (Aluminium, 1.67 Ghz, OS 10.4.7): just like several other users, the temperature sensor that is located under the trackpad has suddenly gone crazy. It started to send random values to the kernel (going from -130°C to +120°C): when this value goes too high the kernel puts the computer in sleep mode. This can happen once in a while or even every few seconds, making the pb unusable. Sometimes it is not even possible to wake the system from sleep or shut it down: I have to remove the battery and wait for the backup battery to drain. My guarantee period has over (less than a month ago! I'm so lucky...) and so I'd spend a lot of money by replacing either the top case or the logic board in the worst case scenario. Every other user on the net that had this problem simply got the hardware parts replaced, but that would be too expensive for me in this moment. The reason why I'm writing all this to a kernel developing mailing list is that I thought about the issue and maybe there could be a way to fix it without replacing any hardware. I'm kinda newbie in that, but I browsed the darwin sources using this darwingrok site http:// darwingrok.physics.ox.ac.uk:8080/source/xref/ and found that this file http://darwingrok.physics.ox.ac.uk:8080/source/xref/ AppleMacRISC4PE/IOPlatformPlugins/PBG4_PlatformPlugin/CtrlLoops/ PBG4_DPSCtrlLoop.cpp (lines 97 and 483), among with others in the PBG4_PlatformPlugin of the AppleMacRISC4PE project, there are references to that specific thermal sensor, as long as methods to get the sensor value. Do you think it's possible to fake the kernel by modifying these lines, to send a hardcoded value just to avoid system craziness, or just comment the lines to avoid that specific sensor checking? The other three sensors are working ok so I don't think this hack would lead to any danger. I tried to compile the AppleMacRISC4PE project but I failed (I think I'm too newbie) even without modifying anything, so I'm asking help to you with this issue. Maybe it's just a small modification. This email sent to site_archiver(a)lists.apple.com

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Re: Theoretical thread limit
by Terry Lambert 25 Jul '06

25 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jul 24, 2006, at 6:55 PM, Guy Sherman wrote: Hi all, Many thanks in advance, Mac OS X Internals: A Systems Approach Amit Singh Addison-Wesley Professional ISBN 0321278542 http://people.freebsd.org/~julian/threads/ This includes a reference to the original Mach threads paper out of CMU. -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I am currently studying operating systems at university and am doing an assignment based around investigating the differences between kernel threads and user threads. Anyhow, I need to be able to find what the theoretical maximum for my machine is. I am running the x86 version of OSX 10.4.7 Tiger. Guy Sherman In MacOS X, for each user space thread, there is a corresponding kernel (Mach) thread, either initially (if the thread is created suspended) or after all the setup is done (if the thread is created running). So MacOS X is technically a 1:1 (1 user thread per 1 kernel thread) threading model in its implementation details. Similar to most systems that support SMP scalability through multithreading, this is the least complicated approach to implement, which is likely why most people implementing threads tend to choose this path. If you want to see a N:1 (N user threads to 1 kernel thread) model, you can look at the threading in FreeBSD 4.3 or thereabouts, or you can look at liblwp in SunOS 4.1.3. There are also a number of preemptive single kernel thread scheduler packages in places like comp.unix.archives (e.g. "sigsched"), though to use them, you will either need to find an older BSD-based system, or you will need to convert the uses of "signal()" to "bsd_signal()", or use "sigaction()" and specify SA_RESTART in the flags so that system calls are automatically restarted, rather than returning EINTR when a signal is received. There are also a number of call conversion scheduler packages out there (i.e. trade a blocking call for a non-blocking call + a context switch). The DEC MTS ("Multi Threading Services") on VMS 5.X is a call conversion scheduler threads package written in Bliss that utilizes VMS asynchronous system traps (ASTs) as a means of triggering context switches. Similarly, you could also look up SA or "Scheduler Activations", which operates on a similar principle. There are also threads packages like "green threads", which are voluntary preemption, user space scheduling utilizing non-blocking I/O (same with "MIT pthreads"). Call conversion schedulers are typically backed by a single kernel thread (N:1), although with approaches like SA, this is not strictly required if you can support thread reentrancy per CPU in your scheduler, and have a way to start up a scheduler context (Sequent, for example, invented an "sfork()" system call for this, where almost everything in the process was shared, except the stack and the scheduler queue; the modern day equivalent is frequently called "rfork()" on systems that implement it). By far, the richest set of implementations you will find on one platform are the FreeBSD implementations in older versions of FreeBSD. For a long time, FreeBSD operated with an N:1 model, implemented an N:M (N user threads for M kernel threads, where N >= M), and at the same time supported a "linux threads" kernel module for Linux-like 1:1 threading. They now have a native 1:1 threading mode in one of their two standard threads libraries. If you want architectural details of MacOS X, you could do worse than to get the book: If you want threads-related information, well, there's a huge amount of information you can find with Google; here's a collection of threads resources put together by Julian Elischer as part of the FreeBSD threads library work: This email sent to site_archiver(a)lists.apple.com

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Re: Theoretical thread limit
by Michael Welch 25 Jul '06

25 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcavkUgEhlTNaxuEEduB+wANk3kyjg== Thread-topic: Theoretical thread limit User-agent: Microsoft-Entourage/11.2.5.060620 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Theoretical thread limit
by Guy Sherman 25 Jul '06

25 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Is there any driver stack change for SCSI drivers from panther to Tiger ?
by Yogesh Pahilwan 24 Jul '06

24 Jul '06

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Re: Is IOUSBFamily/IOKit different for Mac OS X 10.4.7 vs 10.4.6?
by Fernando Urbina 21 Jul '06

21 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Is IOUSBFamily/IOKit different for Mac OS X 10.4.7 vs 10.4.6?
by Terry Lambert 21 Jul '06

21 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com virtual bool isOpen( const IOService * forClient = 0 ) const; -- Terry ////////////// IOUSBDevice * _device; ... ... if ( _device && !_device->isOpen() ) { // Let's attempt to open the device if ( !_device->open(this) ) { err = kIOReturnExclusiveAccess; goto ErrorExit; } } Please comment. Thanks and Regards, -- Rohit Dhamija(M) 9818446545 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/tlambert%40apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… /*! @function isOpen @abstract Determine whether a specific, or any, client has an IOService open. @discussion Returns the open state of an IOService with respect to the specified client, or when it is open by any client. @param forClient If non-zero, isOpen returns the open state for that client. If zero is passed, isOpen returns the open state for all clients. @result Returns true if the specific, or any, client has the IOService open. */ I expect that it worked before because there was another instance of the IOService (IOUSBDevice) open, and so when you passed the 0, you got something other than the one you were actually trying to ask about. You will likely want to correct your code to use "this" on all platforms, since if this is the case, it is only working on older systems by luck (and if so, some customers might have luck while others don't, and you'll get mysterious "doesn't work for me" vs. "can't reproduce" type bug reports from the field). On Jul 21, 2006, at 1:14 PM, rohit dhamija wrote: Some time back , I developed the KEXT for my USB control type transfer device which worked fine on Mac OS X 10.3.9 to Mac OS X 10.4.6 OS X but started failing on the upgraded version of Mac OS X 10.4.7ppc Upon analyzing the code I found that attempting to open the IOUSBDevice was failing for Mac OS X 10.4.7 ppc but the same peice of code worked fine for previous versions of the Mac OS X . Below is the peice of code ////////////// The _device->isOpen() worked fine till Mac OS X 10.4.6 but started failing on Mac OS X 10.4.7ppc. Changing _device->isOpen(this) made the code work for Mac OS X 10.4.7 as well as previous versions Is there any change in IOUSBFamily / IOKit for isOpen() function in Mac OS X 10.4.7 darwin source? Or what may be the reason behind this ? This email sent to tlambert(a)apple.com This email sent to site_archiver(a)lists.apple.com

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Is IOUSBFamily/IOKit different for Mac OS X 10.4.7 vs 10.4.6?
by rohit dhamija 21 Jul '06

21 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:mime-version:content-type; b=V171urXt3BHdLjx7cUZ/Oob7HeNPysOL16i5uAVcN+j9p+y+1UpSYikk/0gRl1GJPO5sxU4WGNLRP598XWEamC0zk8afFnL0fF51DvdulJGlwjksH3uEfn/V5EgS2cqq+4ug0/PVJJeosUe7w7JCzS3pZVe1tjfUVN3rfqbP+a0= _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: page tables in dual and quad G5 systems?
by Michael Smith 20 Jul '06

20 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jul 18, 2006, at 9:56 PM, Parav Pandit wrote: In our xnu kernel, for dual and quad SMP system, do we have individual page table for each processor in the memory? I would encourage you to check out Amit Singh's new book. First the process starts on processor 1 and than if it gets schedule on processor 2 later on, there will be page table update through the page fault. Is that correct understanding? For each active address space, there is necessarily a set of mappings available between virtual and physical addresses. PPC mappings are not particularly like the intel/VAX/etc. style mappings that it sounds like you're familiar with. Are you asking out of curiosity, or is there something specific you are looking for? = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I guess so. This email sent to site_archiver(a)lists.apple.com

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NFSv4 server for xnu-792, interested?
by rick＠snowhite.cis.uoguelph.ca 19 Jul '06

19 Jul '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi, I am trying to decide if I should spend the next few weeks of my spare time porting my NFSv4 server to xnu-792. If you are interested and would download/test a patch for xnu-792.6.70 that is an NFSv4 (also does v2,3 and Kerberized NFS), please email me to let me know. Just trying to find out if there is interest, rick _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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