Subject: Re: Udev coldplugging loads 8139too driver instead of 8139cp

From: Michael Tokarev <[email-masked]>
Date: Tue, 29 Jan 2008 13:43:53 +0300

Stephen Hemminger wrote:
> On Tue, 29 Jan 2008 03:46:08 +0300
> Michael Tokarev <[email-masked]> wrote:
[]
>> There are 2 drivers for 8139-based NICs.  For really different two kinds
>> of hardware, which both uses the same PCI identifiers.  Both drivers
>> "claims" to work with all NICs with those PCI ids, because "externally"
>> (by means of udev for example) it's impossible to distinguish the two
>> kinds of hardware, it becomes clean only when the driver (either of the
>> two) loads and actually checks which hardware we have here.
> 
> Is there any chance of using subdevice or subversion to tell them apart?
> That worked for other vendors like DLINK who slapped same ID on different
> cards.

If it were that simple... ;)

No.  The difference is in PCI revision number (byte #8 in PCI config space).
If it's >= 0x40 - it's 8139too, < 0x40 - 8139cp.  Or 0x20 - I forgot.

Here's a code snippet from a shell script I used ages ago to automatically
load modules (similar to what udev does nowadays):

  # special hack for 8139{too,cp} stuff
  case "$modalias" in
  *v000010ECd00008139*)
    rev="$(dd if="$1/config" bs=1 skip=8 count=1 2>/dev/null)"
    if [ -n "$rev" ]; then
      list=
      for module in $modlist; do
        case "$module" in
        8139cp)
          if [ ".$rev" \< ". " ]; then
            $vecho1 "$TAG: not loading $module for this device"
            continue
          fi
          ;;
        8139too)
          if [ ".$rev" \> ". " ]; then
            $vecho1 "$TAG: not loading $module for this device"
            continue
          fi
          ;;
        esac
        list="$list $module"
      done
      modlist="$list"
    fi
    ;;
  esac

/mjt