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Linux 2.6.33-rc4 Kernel: 40% DRM Changes

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  • Linux 2.6.33-rc4 Kernel: 40% DRM Changes

    Phoronix: Linux 2.6.33-rc4 Kernel: 40% DRM Changes

    One week after pushing out the third release candidate for the Linux 2.6.33 kernel, Linus Torvalds has issued the fourth release candidate. In his mailing list announcement, Linus characterizes the Linux 2.6.33-rc4 kernel as being an "odd release" as a bulk of the changes "all pretty unusual." What got changed? Well, lots of new Direct Rendering Manager (DRM) code ended up getting pulled. Linus noted in his message that around 40% of the changes for this new test release are for the DRM code, largely to do with the ATI Radeon driver as well as the Nouveau driver for NVIDIA hardware that recently went mainline...

    http://www.phoronix.com/vr.php?view=Nzg3Ng

  • #2
    Does anyone know what the "ATI SidePort memory detection for IGPs" part entails?

    I have an 785G motherboard which seems to be sort of working (a few gliches in 3d games like oolite that make them unplayable) with the latest git versions of drm/radeon driver/mesa.

    What differences might I expect to see?

    Tim

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    • #3
      From the patch:

      From 6dda9228a6fa53cbc0ebcba90b111570fecac1cf Mon Sep 17 00:00:00 2001
      From: Alex Deucher <alexdeucher@gmail.com>
      Date: Tue, 5 Jan 2010 11:27:29 -0500
      Subject: [PATCH] drm/radeon/kms: detect sideport memory on IGP chips

      This detects if the sideport memory is enabled and
      if it is VRAM is evicted on suspend/resume.

      This should fix s/r issues on some IGPs.

      Comment


      • #4
        Originally posted by curaga View Post
        From the patch:
        Thanks - I suppose I should have googled for that one.

        Since I don't use suspend / resume on that box that patch probably won't affect my machine.

        That's not to say that there won't be any improvements in this for me, of course; since I got the new m/b + cpu and installed the GIT versions of the drivers, things do seem to have got a bit smoother as time has passed...

        Tim

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        • #5
          I hope this detects my external monitor properly, so whenever KMS is on, I get the correct resolution for it and not that of the laptop's internal resolution.

          Maybe Linus is calling this odd, coz the kernel is slowly being turned into a desktop-oriented kernel with the graphics goodies in ?

          Comment


          • #6
            For the drm fb console, if you have multiple monitors attached, they get set up in clone mode with the best mode common to both heads due to limitations in the kernel fb interface. Once X is up, you can adjust the modes however you like.

            Comment


            • #7
              Originally posted by sundown View Post
              I hope this detects my external monitor properly, so whenever KMS is on, I get the correct resolution for it and not that of the laptop's internal resolution.

              Maybe Linus is calling this odd, coz the kernel is slowly being turned into a desktop-oriented kernel with the graphics goodies in ?
              Kinda, My take on it is that the kernel is undergoing a natural evolution to include more hardware support, and gfx hardware is just the latest set of drivers to get a lot of attention. Surely, the X desktop is the main beneficiary of this drive, but not necessarily the only one.

              Comment


              • #8
                Originally posted by agd5f View Post
                For the drm fb console, if you have multiple monitors attached, they get set up in clone mode with the best mode common to both heads due to limitations in the kernel fb interface. Once X is up, you can adjust the modes however you like.
                Ok surely, but it is pointless to me to have a pretty startup like Plymouth and see the prettiness of it on 1280x800 within my external 1440x900 ... and in the 1440x900 resolution everything that is beyond the 1280x800 resolution is black borders. So it's like a small screen within the larger screen and the space that is not used by the smaller screen in the larger screen is -- black... Am I understood correctly, hehe? Anyway, isn't this a KMS design flaw?

                Comment


                • #9
                  Originally posted by sundown View Post
                  Ok surely, but it is pointless to me to have a pretty startup like Plymouth and see the prettiness of it on 1280x800 within my external 1440x900 ... and in the 1440x900 resolution everything that is beyond the 1280x800 resolution is black borders. So it's like a small screen within the larger screen and the space that is not used by the smaller screen in the larger screen is -- black... Am I understood correctly, hehe? Anyway, isn't this a KMS design flaw?
                  As I said, it's a limitation of the existing kernel fb layer (it has no concept of multiple heads on a single device). We have to use it for compatibility with existing kernel fb stuff. You can use the radeon kms ioctls directly (like X does) and not be subject to this limitation.

                  Comment


                  • #10
                    Well, all these stuff are nice, but the hdmi audio is not working for me at all. OK, you can easily argue that pulseaudio in ubuntu is shitty and probably that causes my problem.
                    But before jumping to that easy conclusion:
                    1) PA could see my hdmi audio device way before I had a driver for it
                    2) PA is rumoured to be good in switching between outputs
                    3) there is nothing in any log files regarding radeon and audio
                    4) when I try to switch between them I get no error messages - anywhere, but I get no sound at all

                    So, what am I doing wrong? Is there anything else which is needed to utilize this gem of code?

                    Thanks for the tips!

                    Comment


                    • #11
                      So, what am I doing wrong? Is there anything else which is needed to utilize this gem of code?
                      What are you using to manage PA?

                      Comment


                      • #12
                        Just the regular stuff called "Sound preferences" (right-click on the icon in the tray). Then in the output tab I can (theoretically) switch between the outputs.

                        Comment


                        • #13
                          Yeah.

                          I just wondering how much PA knew about your hardware. It has the ability to go and configure your hardware's mixers. This is meant to replace the need for users to opening up a terminal and running 'alsamixer' to configure the hardware.

                          This is a feature of newer versions of PA.

                          If Ubuntu uses a slightly older version or if the programmers were not aware of how to work your sound card at the time they made that version then PA probably won't know how to configure your hardware correctly.

                          Usually sound cards support multiple outputs... like headphones, stereo out, digital out, surround sound, etc etc. That is a huge PITA to configure manually and PA can do it correctly for you if it understands the hardware.

                          If you in sound preferences then you can choose between different sound outputs in the 'hardware tab' and 'output tabs'.


                          In that case that PA does not know how to configure your hardware correctly you'll probably have to it manually and fire up 'alsamixer' on the command line and configure the low-level mixers for your hardware so they work.

                          My first guess is just that the HDMI audio out is muted.
                          ------------

                          I know going back to muck around with alsa stuff directly is a huge pain in the ass once your used to dealing with PulseAudio, but it is not too difficult once you know what to expect. A throw back to the 'bad old days' of 'just alsa'.

                          First you need to figure out what card is what. Since you have more then one card then you'll have to use alsamixer to figure out what is what.

                          This can change in between reboots depending on how you have stuff plugged in. Depending on udev, the order they are detected, and all that.


                          alsamixer -c0

                          will access the first card.

                          alsamixer -c1 will acess the second card.

                          etc etc.

                          Don't be surprised if you end up with more then 2 'sound cards'. There are all sorts of virtual sound devices that show up as sound cards to the user. For example I had a webcam with mic input and that showed up as a sound device.

                          For testing sound as you play around with the hardware mixers I like to use 'mplayer'.

                          mplayer -ao alsa:device=hw=0 *mp3

                          will have mplayer output to the first sound card and

                          mplayer -ao alsa:device=hw=1 *mp3

                          Will output to the second.


                          I like having this play while I muck around with the mixers. Make sure no other device is playing music. Typically modern hardware is only able to handle one PCM stream at a time and if you have something playing over PA then it may block access to the hardware.

                          If that is a problem you can probably disable PA by going into gnome-session-properties and unchecking it and logging out and logging back in. Run 'killall pulse-audio' to make sure that it is dead. Depending on how Gnome is setup PA may auto-respawn otherwise.


                          If you get sound output working correctly then Alsa should save the settings and it should work fine with PA after that.

                          Sorry, but that is about the best I can do. I don't have any HDMI devices to test it out on right now otherwise I'd have more of a better step-by-step solution.
                          Last edited by drag; 01-13-2010, 04:33 PM.

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                          • #14
                            Thanks for your exhaustive reply.

                            I did try playing a file with mplayer using alsa outputs. The azalia chip worked, the hdmi remained silent while PA reported it playing sound.
                            It was not muted in any obvious places, though alsa sometimes has nice tricks.

                            Unfortunately I can't test it right away, only when I travel home, but I don't have internet access there. Point is that me not writing back here for a few days is not out of lack of interest, but impossibility.

                            Comment


                            • #15
                              Hdmi audio has to be enabled in the video stream by the GPU driver. Currently you need radeonhd or 2.6.33 for kms. In both cases support is still experimental.

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