Palacio de Cristal

Linux

Just a place to write down my Linux experiences and if I find some information or news items that I think are really worthwile I'll probably mention them here as well.

Ok, just learned that having two sound cards in your system can lead to all kinds of trouble.

Some time ago I had bought some headphones from Altec Lansing that came with an USB adapter. Not expecting it to work in Linux I plugged it in, but lo and behold it actually worked and I had now two sound cards in my system according to Fedora's Soundcard Detection utility. So far so good.

Soon after I removed the USB module and just connected the headphones directly like I had always done and life was perfect.

Until quite some time later I had to reboot my machine and suddenly I was getting all these weird ALSA errors from all kinds of programs (see for example the image of the pop-up that appeared at KDE startup).

The strange thing was that the Soundcard Detection program reported everything okay, the right sound card was detected, I could hear the sample and on top of that several programs did actually produce sound. So what was going on here?

Finally today I got a hint trying to run alsamixer when it gave me the following error:

alsamixer: function snd_ctl_open failed for default: No such device

Now this was something I could google for. So I ended up with several leads of which two led to the final solution:

ALSA user list which didn't really have a direct solution for my problem, but it made me look at the modules where I found snd-usb-audio. So what was that doing there when I had removed that USB adapter ages ago? Of course /etc/modprobe.conf was the "culprit" here. Somehow plugging in the USB adapter had inserted some lines into the file but removing the adapter hadn't deleted them!
LinuxQuestions.org pointed me to some files I had never heard off: /etc/asound.state and /etc/asound.conf. The first didn't seem too interesting, but the second had things like card numbers which made me think that maybe they had gotten mixed up somehow because for a short time I had two sound cards in my system. So I removed both and restarted the Soundcard Detection program. And like I had imagined the numbers were different in the new asound.conf!

So everything seems to work again. Now to figure out why the microphone only picks up sounds very faintly.

Well, at least we know now how Linus feels about Windows:

I'm not claiming that the current code cannot work. It clearly *does* work for a lot of people. But I'm claiming that it's STUPID. So don't argue that "it works". Windows works, kind of. That doesn't make it less stupid and badly designed!

Linus must have been in one of his poetic moods again ;-)

It's one of those rare 'perfect' kernels. So if it doesn't happen to compile with your config (or it does compile, but then does unspeakable acts of perversion with your pet dachshund), you can rest easy knowing that it's all your own d*mn fault, and you should just fix your evil ways.

Yesterday I upgraded our Dell Latitude to FC6, it was running FC4 and it was getting difficult to encounter some of the packages that I use on the desktop system (like Twinkle

for example).

Well I can tell you that the installation went a whole lot better compared to the problems I had with the desktop machine!

There was just one thing that bothered me. Where the desktop actually seemed faster (as it was supposed to according to this, see the Performance section) the latop felt sluggish somehow. Applications were taking too long to load. When I tried measuring the drive's performance I got this:


root# hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads:  48 MB in  3.65 seconds =  13.15 MB/sec

which is way too slow for that drive. Then I remembered that I had the same problem before with this laptop and it was because of the polling KDED did of the CD rom drive (to detect media changes and such). Stopping KDED (which you can do in the KDE Control Center -> KDE Components -> Service Manager) would solve the problem.

But with FC6 this didn't seem to help. I found an option called Enable CD polling in the Peripherals -> Storage Media of the Control Center, but the option was grayed out so I couldn't change it.

I finally found out today that it is HAL which does the polling nowadays, specifically the hald-addon-storage module. Killing it restored the expected performance:


root# hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads:  106 MB in  3.02 seconds =  35.15 MB/sec

So now it was time to figure out if something could be done about it. According to to this forum message

it is a known problem with Dell laptops but it seems that the blacklisting it talks about doesn't work (anymore) in FC6.

In the end I found out that HAL uses a set of rules to determine what to do with certain hardware which are stored in /usr/share/hal/fdi. By doing a lshal I could get a list of all the detected devices and find the information about the particular CD drive used in the laptop:


udi = '/org/freedesktop/Hal/devices/pci_8086_248a_ide_0_1'
  info.udi = '/org/freedesktop/Hal/devices/pci_8086_248a_ide_0_1'  (string)
  linux.subsystem = 'ide'  (string)
  linux.hotplug_type = 1  (0x1)  (int)
  info.product = 'IDE device (slave)'  (string)
  ide.channel = 1  (0x1)  (int)
  ide.host = 0  (0x0)  (int)
  info.linux.driver = 'ide-cdrom'  (string)
  info.parent = '/org/freedesktop/Hal/devices/pci_8086_248a'  (string)
  info.bus = 'ide'  (string)
  linux.sysfs_path_device = '/sys/devices/pci0000:00/0000:00:1f.1/ide0/0.1'  (string)
  linux.sysfs_path = '/sys/devices/pci0000:00/0000:00:1f.1/ide0/0.1'  (string)

udi = '/org/freedesktop/Hal/devices/storage_model_HL_DT_STCD_RW/DVD_ROM_GCC_4240N'
  org.freedesktop.Hal.Device.Storage.method_execpaths = {'hal-storage-eject', 'hal-storage-closetray'} (string list)
  org.freedesktop.Hal.Device.Storage.method_argnames = {'extra_options', 'extra_options'} (string list)
  org.freedesktop.Hal.Device.Storage.method_signatures = {'as', 'as'} (string list)
  org.freedesktop.Hal.Device.Storage.method_names = {'Eject', 'CloseTray'} (string list)
  info.interfaces = {'org.freedesktop.Hal.Device.Storage', 'org.freedesktop.Hal.Device.Storage'} (string list)
  info.addons = {'hald-addon-storage'} (string list)
  block.storage_device = '/org/freedesktop/Hal/devices/storage_model_HL_DT_STCD_RW/DVD_ROM_GCC_4240N'  (string)
  info.udi = '/org/freedesktop/Hal/devices/storage_model_HL_DT_STCD_RW/DVD_ROM_GCC_4240N'  (string)
  storage.cdrom.write_speed = 4234  (0x108a)  (int)
  storage.cdrom.read_speed = 4234  (0x108a)  (int)
  storage.cdrom.support_media_changed = true  (bool)
  storage.cdrom.hddvdrw = false  (bool)
  storage.cdrom.hddvdr = false  (bool)
  storage.cdrom.hddvd = false  (bool)
  storage.cdrom.bdre = false  (bool)
  storage.cdrom.bdr = false  (bool)
  storage.cdrom.bd = false  (bool)
  storage.cdrom.dvdplusrdl = false  (bool)
  storage.cdrom.dvdplusrwdl = false  (bool)
  storage.cdrom.dvdplusrw = false  (bool)
  storage.cdrom.dvdplusr = false  (bool)
  storage.cdrom.dvdram = false  (bool)
  storage.cdrom.dvdrw = false  (bool)
  storage.cdrom.dvdr = false  (bool)
  storage.cdrom.dvd = true  (bool)
  storage.cdrom.cdrw = true  (bool)
  storage.cdrom.cdr = true  (bool)
  storage.requires_eject = true  (bool)
  storage.hotpluggable = false  (bool)
  info.capabilities = {'storage', 'block', 'storage.cdrom'} (string list)
  info.category = 'storage'  (string)
  info.product = 'HL-DT-STCD-RW/DVD-ROM GCC-4240N'  (string)
  storage.size = 0  (0x0)  (uint64)
  storage.removable = true  (bool)
  storage.removable.media_available = false  (bool)
  storage.physical_device = '/org/freedesktop/Hal/devices/pci_8086_248a_ide_0_1'  (string)
  storage.firmware_version = 'D110'  (string)
  storage.vendor = ''  (string)
  storage.model = 'HL-DT-STCD-RW/DVD-ROM GCC-4240N'  (string)
  storage.drive_type = 'cdrom'  (string)
  storage.automount_enabled_hint = true  (bool)
  storage.media_check_enabled = true  (bool)
  storage.no_partitions_hint = true  (bool)
  storage.bus = 'ide'  (string)
  block.is_volume = false  (bool)
  block.minor = 64  (0x40)  (int)
  block.major = 3  (0x3)  (int)
  block.device = '/dev/hdb'  (string)
  linux.hotplug_type = 3  (0x3)  (int)
  info.parent = '/org/freedesktop/Hal/devices/pci_8086_248a_ide_0_1'  (string)
  linux.sysfs_path_device = '/sys/block/hdb'  (string)
  linux.sysfs_path = '/sys/block/hdb'  (string)

Using the information above I created my own fdi file information/30private/10-crappy-dell-cddrive.fdi with the following rules:


<deviceinfo version="0.2">
  <device>

    <!-- Prevent polling on CD-Rom drive -->
    <match key="storage.model" string="HL-DT-STCD-RW/DVD-ROM GCC-4240N">
      <merge key="storage.media_check_enabled" type="bool">false<merge>
    <match>

  <device>
<deviceinfo>

service haldaemon restart) everything was back to normal. Of course the system won't automatically detect any CDs being inserted into the drive, but I can live with that. (And yes, of course I filed a bug report

)