From f932415c8ac26fd7bb7c20903e0a897dfbb44f81 Mon Sep 17 00:00:00 2001
From: Jean Delvare <khali@linux-fr.org>
Date: Thu, 27 Nov 2008 17:44:12 +0000
Subject: [PATCH] Fix bus number prediction logic (#2327). We don't need
 anything complex, given how rare are the cases where this really matters. On
 most systems we will only load one I2C bus driver, so the bus numbers simply
 can't change.

git-svn-id: http://lm-sensors.org/svn/lm-sensors/branches/lm-sensors-3.0.0@5441 7894878c-1315-0410-8ee3-d5d059ff63e0
---
 CHANGES                    |   1 +
 prog/detect/sensors-detect | 100 ++++++++++++++++---------------------
 2 files changed, 43 insertions(+), 58 deletions(-)

diff --git a/CHANGES b/CHANGES
index 7f1d8f67..23e81d5f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -28,6 +28,7 @@ SVN-HEAD
                   Unload kernel drivers when we are done with them (#2329)
                   Fix handling of bus driver names with an underscore
                   Simplify loading of bus drivers
+                  Fix bus number prediction logic (#2327)
 
 3.0.3 (2008-09-28)
   libsensors: Avoid namespace pollution
diff --git a/prog/detect/sensors-detect b/prog/detect/sensors-detect
index a18d7cea..343f7f4e 100755
--- a/prog/detect/sensors-detect
+++ b/prog/detect/sensors-detect
@@ -5135,37 +5135,47 @@ sub print_chips_report
   }
 }
 
-# We build here an array adapters, indexed on the number the adapter has
-# at this moment (we assume only loaded adapters are interesting at all;
-# everything that got scanned also got loaded). Each entry is a reference
-# to a hash containing:
-#  driver: Name of the adapter driver
-#  nr_now: Number of the bus now
-#  nr_later: Number of the bus when the modprobes are done (not included if the
-#        driver should not be loaded)
-# A second array, called
 sub generate_modprobes
 {
-  my ($chip, $detection, $nr, $i, @optionlist, $driver, $isa, $adap);
+  my ($chip, $detection, @optionlist, $isa, $adap);
   my $ipmi = 0;
-  my $modprobes = "";
+  my $modprobes;
   my $configfile;
 
-  # Collect all adapters used
-  $nr = 0;
+  # Handle aliases
+  # As of kernel 2.6.28, alias detection is handled by kernel drivers
+  # directly, so module options are no longer needed.
+  unless (kernel_version_at_least(2, 6, 28)) {
+    foreach $chip (@chips_detected) {
+      @optionlist = ();
+      foreach $detection (@{$chip->{detected}}) {
+        if (exists $detection->{i2c_driver} and
+            exists $detection->{isa_addr}) {
+          push @optionlist, $detection->{i2c_devnr},
+                            $detection->{i2c_addr};
+        }
+      }
+
+      next if not @optionlist;
+      $configfile = "# hwmon module options\n" unless defined $configfile;
+      $configfile .= "options $chip->{driver}";
+      $configfile .= sprintf(" ignore=%d,0x%02x", shift @optionlist,
+                                                  shift @optionlist);
+      $configfile .= sprintf(",%d,0x%02x", shift @optionlist,
+                             shift @optionlist) while @optionlist;
+      $configfile .= "\n";
+    }
+  }
+
   $isa = 0;
   foreach $chip (@chips_detected) {
     foreach $detection (@{$chip->{detected}}) {
-      # If there is more than one bus detected by a driver, they are
-      # still all added. So we number them in the correct order
-      if (exists $detection->{i2c_driver} and
-          not exists $i2c_adapters[$detection->{i2c_devnr}]->{nr_later} and
-          not exists $detection->{isa_addr}) { # Always use ISA access if possible
-         foreach $adap (@i2c_adapters) {
-           next unless exists $adap->{driver};
-           $adap->{nr_later} = $nr++ if $adap->{driver} eq $detection->{i2c_driver};
-         }
+      # Tag adapters which host hardware monitoring chips we want to access
+      if (exists $detection->{i2c_devnr}
+       && !exists $detection->{isa_addr}) {
+           $i2c_adapters[$detection->{i2c_devnr}]->{used}++;
       }
+
       if (exists $detection->{isa_addr}) {
            $isa = 1;
       }
@@ -5175,19 +5185,17 @@ sub generate_modprobes
     }
   }
 
-  $modprobes .= "# I2C adapter drivers\n" if $nr;
-  for ($i = 0; $i < $nr; $i++) {
-    foreach $adap (@i2c_adapters) {
-      next unless exists $adap->{nr_later} and $adap->{nr_later} == $i;
-      if ($adap->{driver} eq "UNKNOWN") {
-        $modprobes .= "# modprobe unknown adapter ".$adap->{name}."\n";
-      } else {
-        $modprobes .= "modprobe $adap->{driver}\n"
-          unless $modprobes =~ /modprobe $adap->{driver}\n/;
-      }
-      last;
-    }
+  # If we added any module option to handle aliases, we need to load all
+  # the adapter drivers so that the numbers will be the same. If not, then
+  # we only load the adapter drivers which are useful.
+  foreach $adap (@i2c_adapters) {
+    next unless contains($adap->{driver}, @modules_we_loaded);
+    next if not defined $configfile and not $adap->{used};
+    $modprobes .= "# I2C adapter drivers\n" unless defined $modprobes;
+    $modprobes .= "modprobe $adap->{driver}\n"
+      unless $modprobes =~ /modprobe $adap->{driver}\n/;
   }
+
   # i2c-isa is loaded automatically (as a dependency) since 2.6.14,
   # and will soon be gone.
   $modprobes .= "modprobe i2c-isa\n" if ($isa && !kernel_version_at_least(2, 6, 18));
@@ -5222,30 +5230,6 @@ sub generate_modprobes
        }
        $modprobes .= "modprobe $chip->{driver}\n";
     }
-
-    # Handle aliases
-    # As of kernel 2.6.28, alias detection is handled by kernel drivers
-    # directly, so module options are no longer needed.
-    unless (kernel_version_at_least(2, 6, 28)) {
-      foreach $detection (@{$chip->{detected}}) {
-        if (exists $detection->{i2c_driver} and
-            exists $detection->{isa_addr} and
-            exists $i2c_adapters[$detection->{i2c_devnr}]->{nr_later}) {
-          push @optionlist, $i2c_adapters[$detection->{i2c_devnr}]->{nr_later},
-                            $detection->{i2c_addr};
-        }
-      }
-    }
-
-    next if not @optionlist;
-    $configfile = "# hwmon module options\n" unless defined $configfile;
-    $configfile .= "options $chip->{driver}";
-    $configfile .= sprintf(" ignore=%d,0x%02x", shift @optionlist,
-                                               shift @optionlist)
-                  if @optionlist;
-    $configfile .= sprintf(",%d,0x%02x", shift @optionlist, shift @optionlist)
-                  while @optionlist;
-    $configfile .= "\n";
   }
 
   return ($modprobes, $configfile);