On Mon, Mar 19, 2007 at 01:32:15AM +0100, Rene Herman wrote: > > I just now tested this on a standalone Jazz16 and it seems to be working > fine for me. I once had ogg123 segfault on me at the end of playback but > was unsuccesful in reproducing -- may have been a fluke. Thanks. I'll try out ogg123. > As to the comments... > > The changes to the SB code to support the Jazz16 I ofcourse agree with. > Supporting a new card is great. I am however not a huge fan of the new > PnP protocol. It's cute, but I feel it's a little over-engineered and > could just as well live directly in snd-jazz16. See below. > This setup also shares that same problem with the BIOS generally not > having reserved/routed the resources -- on a general PCI/ISA system the > user needs to go into the BIOS setup and reserve the resources the card > is (or will be, in this case) set to. So now the user really needs to > know what resources are going to be assigned, destroying the plug and > play idea... Not really. A standards compliant PnPBIOS set up with "PnP aware OS = YES" will use only enough resources to boot the system, which should leave enough irqs and dmas for the Linux PnP layer to do its work. I think there are three good reasons to use the PnP layer: 1) The PnP layer informs the PCI layer of irqs to try to avoid - please see pnp_register_irq_resource() in drivers/pnp/resource.c. 2) The PnP layer knows which resources are used by active devices, even if they have not been allocated using e.g. request_region(). This happens in practice. For example: $ cat /sys/bus/pnp/devices/01\:02.00/resources state = active io 0x2a0-0x2af io 0x390-0x393 io 0x500-0x50f irq 5 dma 0 dma 1 $ cat /proc/ioports [...] 0200-0200 : ns558-pnp 0201-0201 : ns558-pnp 0208-020f : ns558-pnp 0213-0213 : ISAPnP 0280-028f : ES18xx 0356-0356 : ide2 0360-0361 : MPU401 UART 0376-0376 : 0000:00:07.1 0376-0376 : ide1 0390-0391 : OPL2/3 (left) 0392-0393 : OPL2/3 (right) 03c0-03df : vga+ 03e8-03ef : serial 03f6-03f6 : 0000:00:07.1 03f6-03f6 : ide0 03f8-03ff : serial 0500-050f : AD1816A 0800-0807 : ES18xx - CTRL [...] Notice that 0x2a0-0x2af is missing from /proc/ioports. The PnP layer will avoid using that port range because it knows a device is using it. 3) Knowing which resources a card can utilize, the PnP layer can try to stay away from those resources when configuring other cards. The PnP layer doesn't do that yet in a stock kernel, but I've patched it to do so. I'll try to get those patches into the kernel. An advantage of autoprobing in a PnP protocol driver (as opposed to doing so in a sound card driver) is that it happens before any file systems have been mounted, so if the autoprobe happens to find one of those #%!$@ NE2000 cards and lock up the system, it won't corrupt your disks. -- Rask Ingemann Lambertsen ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
