Re: BootX
Hi, I have looked at the -S output for mesh.c from both 4.1.2 and 4.3.5. The generated code is quite different but I can not see any difference that is causing the problem? If I read and print the bus status register 0, it does appear to have the busy bit set? I'm in way over my head here. It appears to complete a pair of inquiries (one with a small data buffer and a second with a larger one) to each target. It then tries a test unit ready but discovers the bus busy? ANY suggestions welcome and appreciated! Thanks! ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, FYI: This driver has some pretty good diagnostics/debug capabilities built in. Once that is enabled it shows that the inquiry works and the sync negotiation works. The next command (I think) is test unit ready, which does not work. It is retried multiple times. The result is 2 which I think is DID_BUS_BUSY. Probably in mesh_start_cmd(), possibly something off in the loop at line 462? kevin P.S.: I posted some documentation for dump_stack()/show_stack() but have not heard anything? Is that not something we are interested in doing? ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Fri, 2011-02-04 at 11:21 -0600, kevin diggs wrote: P.S.: I posted some documentation for dump_stack()/show_stack() but have not heard anything? Is that not something we are interested in doing? Or I haven't had a chance to review it yet ... I'm very very busy at the moment so things are lagging a bit. Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, FYI: I have narrowed this down to drivers/scsi/mesh.c (the root disk controller for the PowerMac 8600). I have compiled everything else for 2.6.36 with 4.3.5, including modules. With a 4.1.2 compiled mesh.c the beast boots. I am using it to post this follow up. kevin On Sat, Jan 22, 2011 at 12:24 PM, kevin diggs diggskevi...@gmail.com wrote: Hi, If I enable SMP then I can build a 2.6.28 kernel with gcc 4.3.5 that WILL boot on the PowerMac8600 (single 750GX). The previously mentioned G4 that runs is a dual cpu beast and thus also runs SMP. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Wed, 2011-02-02 at 13:36 -0600, kevin diggs wrote: Hi, FYI: I have narrowed this down to drivers/scsi/mesh.c (the root disk controller for the PowerMac 8600). I have compiled everything else for 2.6.36 with 4.3.5, including modules. With a 4.1.2 compiled mesh.c the beast boots. I am using it to post this follow up. That's interesting... That driver is really nasty, we probably have a bug in it that's exposed by optimizations done by more recent compilers but it's not going to be trivial to figure out I'm afraid. I at least have very dim memories of mesh and how it operates... One thing to be careful of with Mesh is that the DMA engine, while supposedly cache coherent, has shown in the past to have issues when DMA'ing to unaligned memory locations. This shouldn't be a problem with normal block transfers but we may have to be careful with things like inquiry, mode pages, sense requests etc... Ben. kevin On Sat, Jan 22, 2011 at 12:24 PM, kevin diggs diggskevi...@gmail.com wrote: Hi, If I enable SMP then I can build a 2.6.28 kernel with gcc 4.3.5 that WILL boot on the PowerMac8600 (single 750GX). The previously mentioned G4 that runs is a dual cpu beast and thus also runs SMP. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Ben, I know you are VERY busy. I appreciate your taking the time to reply. Since I'm am still using this thing I'll take a stab at trying to track it down. I just posted the FYI to see if I could trigger some thoughts (like your post). With a 4.3.5 compiled mesh, it fails a lot of early stuff like getting cache info? I don't remember the full list because it fails to find the root fs and does the reboot in 180 seconds thing (I still have in a back corner of my brain the serial console xmon boot stuff and will probably eventually try that). I am hopeful that since it (at least so far) always fails that it might not be THAT bad to track down. That coupled with some knowledge of what the compilers are doing differently can hopefully help track it down. Thanks! kevin On Wed, Feb 2, 2011 at 3:40 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: That's interesting... That driver is really nasty, we probably have a bug in it that's exposed by optimizations done by more recent compilers but it's not going to be trivial to figure out I'm afraid. I at least have very dim memories of mesh and how it operates... One thing to be careful of with Mesh is that the DMA engine, while supposedly cache coherent, has shown in the past to have issues when DMA'ing to unaligned memory locations. This shouldn't be a problem with normal block transfers but we may have to be careful with things like inquiry, mode pages, sense requests etc... Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, And one more thing: Why does an SMP kernel (mesh compiled in an SMP enabled kernel) work? What all does SMP do? If it matters, I'm voluntary preempt. Is the DMA hardware in this thing used in any other system (I guess I mean both other computers and other sub-systems in this computer - does the 53c94 use it? The audio uses it, right?)? kevin ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Wed, 2011-02-02 at 16:09 -0600, kevin diggs wrote: Hi, And one more thing: Why does an SMP kernel (mesh compiled in an SMP enabled kernel) work? Could be an alignment or timing problem, depending on random things the alignment of some DMA data structures or timing of access might end up being subtely different. What all does SMP do? If it matters, I'm voluntary preempt. Is the DMA hardware in this thing used in any other system (I guess I mean both other computers and other sub-systems in this computer - does the 53c94 use it? The audio uses it, right?)? The DBDMA engine is used in various Apple chips but with more or less HW bugs in it :-) To get some more info about the MESH, I suggest you google for a document called MacTech.pdf (Macintosh Technology in the Common Hardware Reference Platform). This describes the MacIO chip that was designed by Apple for CHRP machines, which is a successor of the Bandit chip which I think contains the MESH on your machine. The basic IO cells like MESH are the same (tho it's possible that the one you have contains more bugs). Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, I've never done any real kernel debugging. Can anyone give any pointers on how to do early boot debugging on an old world (buggy OF) powermac? Can I do anything using a serial console? A little reading last night suggested that spinlocks are supposed to disappear for single processor machines. I do not understand why they are present in 3.4.6 (at least the symbol anyway)? The 'acct_lock' spin lock was also missing with gcc 4.2.4. kevin On Sat, Jan 22, 2011 at 12:24 PM, kevin diggs diggskevi...@gmail.com wrote: Hi, If I enable SMP then I can build a 2.6.28 kernel with gcc 4.3.5 that WILL boot on the PowerMac8600 (single 750GX). The previously mentioned G4 that runs is a dual cpu beast and thus also runs SMP. I at least know this (ok, I THINK I know): For non-SMP: The spinlock 'acct_lock' in kernel/acct.c that IS present in 3.4.6 (i.e. kernel 2.6.28 compiled with gcc 3.4.6). Not so much for 4.3.5. I have not yet done a general 4.3.5 compiled 2.6.28 spinlock safari. Don't some funky, optimizery things happen to spinlocks for the NON-smp case? I'll see what the 4.2.x gcc does. Thanks! kevin P.S.: There is one other difference for the SMP 4.3.5 compiled 2.6.28: my 750gx cpufreq driver gets disabled. It is fairly isolated code though. Should not be able to nuke the spinlock in kernel/acct.c On Fri, Jan 21, 2011 at 1:26 PM, kevin diggs diggskevi...@gmail.com wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? kevin ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, If I enable SMP then I can build a 2.6.28 kernel with gcc 4.3.5 that WILL boot on the PowerMac8600 (single 750GX). The previously mentioned G4 that runs is a dual cpu beast and thus also runs SMP. I at least know this (ok, I THINK I know): For non-SMP: The spinlock 'acct_lock' in kernel/acct.c that IS present in 3.4.6 (i.e. kernel 2.6.28 compiled with gcc 3.4.6). Not so much for 4.3.5. I have not yet done a general 4.3.5 compiled 2.6.28 spinlock safari. Don't some funky, optimizery things happen to spinlocks for the NON-smp case? I'll see what the 4.2.x gcc does. Thanks! kevin P.S.: There is one other difference for the SMP 4.3.5 compiled 2.6.28: my 750gx cpufreq driver gets disabled. It is fairly isolated code though. Should not be able to nuke the spinlock in kernel/acct.c On Fri, Jan 21, 2011 at 1:26 PM, kevin diggs diggskevi...@gmail.com wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? kevin ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Fri, 2011-01-21 at 13:26 -0600, kevin diggs wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? It's possible. Have you tried using OF booting instead ? The 8600 should be cable to boot off SCSI or netboot COFF images. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, This would require quik, right? I went to penguinppc.org and tried to get the latest BootX and quik but the links are dead. Do you know where the latest versions are? kevin On Fri, Jan 21, 2011 at 3:21 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 13:26 -0600, kevin diggs wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? It's possible. Have you tried using OF booting instead ? The 8600 should be cable to boot off SCSI or netboot COFF images. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Fri, 2011-01-21 at 19:48 -0600, kevin diggs wrote: Hi, This would require quik, right? I went to penguinppc.org and tried to get the latest BootX and quik but the links are dead. Do you know where the latest versions are? That link still works: kevin On Fri, Jan 21, 2011 at 3:21 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 13:26 -0600, kevin diggs wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? It's possible. Have you tried using OF booting instead ? The 8600 should be cable to boot off SCSI or netboot COFF images. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Fri, 2011-01-21 at 19:48 -0600, kevin diggs wrote: Hi, This would require quik, right? I went to penguinppc.org and tried to get the latest BootX and quik but the links are dead. Do you know where the latest versions are? That link still works: Oops... typing FAIL :-) I meant: http://penguinppc.org/bootloaders/quik/ However, it's possible that distros like debian have done more changes to it. Another option is to netboot a zImage directly, which works if it's not too big. Cheers, Ben. kevin On Fri, Jan 21, 2011 at 3:21 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 13:26 -0600, kevin diggs wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? It's possible. Have you tried using OF booting instead ? The 8600 should be cable to boot off SCSI or netboot COFF images. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
Hi, The link: http://www.shiner.info/?files/Yellow%20Dog%20Linux%204/quik to download the latest source does not seem to have anything useful??? kevin On Fri, Jan 21, 2011 at 7:50 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 19:48 -0600, kevin diggs wrote: Hi, This would require quik, right? I went to penguinppc.org and tried to get the latest BootX and quik but the links are dead. Do you know where the latest versions are? That link still works: Oops... typing FAIL :-) I meant: http://penguinppc.org/bootloaders/quik/ However, it's possible that distros like debian have done more changes to it. Another option is to netboot a zImage directly, which works if it's not too big. Cheers, Ben. kevin On Fri, Jan 21, 2011 at 3:21 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 13:26 -0600, kevin diggs wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? It's possible. Have you tried using OF booting instead ? The 8600 should be cable to boot off SCSI or netboot COFF images. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: BootX
On Fri, 2011-01-21 at 20:03 -0600, kevin diggs wrote: Hi, The link: http://www.shiner.info/?files/Yellow%20Dog%20Linux%204/quik to download the latest source does not seem to have anything useful??? Ah right. 2.0e is still there tho. Try to have a look at what's in distros like debian or genpoo.. Cheers, Ben. kevin On Fri, Jan 21, 2011 at 7:50 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 19:48 -0600, kevin diggs wrote: Hi, This would require quik, right? I went to penguinppc.org and tried to get the latest BootX and quik but the links are dead. Do you know where the latest versions are? That link still works: Oops... typing FAIL :-) I meant: http://penguinppc.org/bootloaders/quik/ However, it's possible that distros like debian have done more changes to it. Another option is to netboot a zImage directly, which works if it's not too big. Cheers, Ben. kevin On Fri, Jan 21, 2011 at 3:21 PM, Benjamin Herrenschmidt b...@kernel.crashing.org wrote: On Fri, 2011-01-21 at 13:26 -0600, kevin diggs wrote: Hi, Anyone familiar with BootX? Could my problems with the 8600 be related to some interaction with BootX? It's possible. Have you tried using OF booting instead ? The 8600 should be cable to boot off SCSI or netboot COFF images. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
