Bug#72479: Data Access Exception
Adam Di Carlo wrote: >Alan Bain <[EMAIL PROTECTED]> writes: > >> I do think something should >> go in the installation manual for the SPARC version about suggesting >> that the lowest memory block be contiguous. > >> I've checked version 2.2.17 of the install instructions and there is no >> mention of the problem, which I've confirmed exists on quite a few Suns. >> I'm happy to write a suitable couple of paragraphs (possibly to go >> in section 3.3.4 Bad Memory Modules). However I'm not sure to whom I >> should send this. > >Just send the text to be added to the bug report -- I'll catch it and >include it. Here is some hopefully useful instructions. - Memory Configuration Some older Sun workstations, notably the Sun IPX and Sun IPC have memory banks located at fixed locations in physical memory. Thus if the banks are not filled gaps will exist in the physical memory space. The Linux installation requires a contiguous memory block into which to load the kernel and the initial ramdisk. If this is not available a `Data Access Exception' will result. Thus you must configure the memory so that the lowest memory block is contiguous for at least 8Mb. In the IPX and IPC cited above, memory banks are mapped in at 16Mb boundaries. In effect this means that you must have a sufficiently large SIMM in bank zero to hold the kernel and ramdisk. In this case 4Mb is NOT sufficient. Example: In a Sun IPX you have a 16Mb SIMM and a 4Mb SIMM. There are four SIMM banks (0,1,2,3). [Bank zero is that furthest away from the SBUS connectors]. You must therefore install the 16Mb SIMM in bank 0; it is then recommended to install the 4Mb SIMM in bank 2. Graphics Configuration -- Especially in the case of older Sun workstations, it is very common for there to be an onboard framebuffer which has been superseeded (for example the bwtwo on a sun IPC), and an SBUS card containing a later probably accelerated buffer is then plugged in to an SBUS slot. Under Solaris/SunOS this causes no problems because both cards are initialised. However with Linux this can cause a problem, in that the bootprom monitor may display its output on this additional card; however the linux kernel boot messages may then be directed to the original on board framebuffer, leaving NO error messages on the screen, with the machine apparently stuck loading the Ram Disk. To avoid this problem, connect the monitor (if required) to the video card in the lowest numbered SBUS slot (on motherboard card counts as below external slots). Alternatively it is possile to use a serial console. -- Alan Bain -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Bug#72479: Data Access Exception
> > Well, it certainly seems like this is an obscure SPARC hardware > problem and you seem to have fixed it. > > Do you mind if I close this bug? We don't really maintain any > information on all the minutae of how to configure hardware for use > with Linux -- there are SPARC/Linux HOWTOs and stuff for that... > I don't mind at all (the bug being closed). I'd spent two days fighting with the problem before filing a bug report. As usual I only solved the problem after filing the bug report. I do think something should go in the installation manual for the SPARC version about suggesting that the lowest memory block be contiguous. I've checked version 2.2.17 of the install instructions and there is no mention of the problem, which I've confirmed exists on quite a few Suns. I'm happy to write a suitable couple of paragraphs (possibly to go in section 3.3.4 Bad Memory Modules). However I'm not sure to whom I should send this. Alan -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Bug#72479: Further details on Data Access Exception
To test the theory of memory locations I borrowed some more RAM. I can confirm that in a Sun IPX the following memory configurations work Bank 0 16Mb 16Mb 16Mb 1 16Mb 4Mb16Mb 2 4Mb 4Mb 3 4Mb 4Mb And that the following DOES NOT work Bank 04Mb 14Mb 24Mb 34Mb [Gives Data Access Exception on loading Ramdisk] My other problem turns out to be that the Sun has two framebuffers, an onboard CG6 (which developed a fault) and a CG3 in an SBUS slot. Bootwas from this second CG3 in the sbus slot; however I saw nothing because all the linux kernel output was on the CG6 on the M/B. At the very least these would be useful FAQ entries! I have a lot of machines with two framebuffers, usually IPCs which has a colour CG3 added to supersede the on board BW2. I suspect this could show the same trouble. Incidentally the IPC memory is configured as 3 banks of 4Mb and this generates the same problem. Alan Bain -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Bug#72479: Data Access Exception
Hunting through some dusty sun hardware manuals reminds me of the following which may be causing my problem. In the IPX there are 4 memory banks which can hold either a 1Mb (silly!), 4Mb, 8Mb or 16Mb SIMM (72 pin parity). The memory is not contiguous and each block is mapped onto a 16Mb boundary, creating memory gaps. The IPX which wont boot has 4 8Mb SIMMs making non-contiguous memory. My IPX which boots OK has one 16MB SIMM. Thus 0-16Mb is a contiguous block. Maybe there is an erroneous hardcoded address which the RAMdisk runs into by using direct physical memory access instead of going through the MMU allocation procedures. Alan Bain -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Bug#72479: Data Access Exception
Package: boot-floppies Version: Debian architecture: sparc model: IPX/IPC memory: 32MB scsi: ESP cd-rom: Toshiba (Sun CD-ROM) network card: le0 I have been having trouble installing Debian Sparc on a number of machines. The CD-ROM set worked fine on one of my machines (IPX, 16Mb RAM). I am using the same CD-ROM drive (genuine Sun 512 byte blocks) on all machines. I have even tried borrowing a spare Toshiba PC SCSI CDROM which has exactly the same effects. Sun IPX (Bootprom version 2.3) 32Mb Machine used to run NetBSD/SunOS fine. The bootprom is rather old. Using CG3 framebuffer (not the onboard CG6) ok> boot cdrom [press return at prompt] loads kernel, then loads ramdisk. The spinner then stops and the machine crashes. L1+A does not return to the boot monitor, a full power cycle is needed. Sun IPC (bootprom version 2.9) 12Mb RAM Using onboard BW2 FB ok> boot cdrom [press return at prompt] Loads kernel. Displays Loading initial ramdisk and then stops with a Data Access Exception Both machines pass all self tests in the Bootprom and used to run SunOS 4.1.1 without trouble. I get similar results with another IPC (even older bootprom) which doesn't understant boot cdrom; but a suitable incantation makes it boot. I'd be grateful for any suggestions! Alan Bain -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
