Re: problems with using the -rc kernel in the git tree

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On Mon, Dec 20, 2010 at 1:54 PM, Theodore Kilgore
<kilgota@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
>
> On Mon, 20 Dec 2010, Alex Deucher wrote:
>
>> On Sun, Dec 19, 2010 at 6:56 PM, Theodore Kilgore
>> <kilgota@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>> >
>> > Hans,
>> >
>> > Thanks for the helpful advice about how to set up a git tree for current
>> > development so that I can get back into things.
>> >
>> > However, there is a problem with that -rc kernel, at least as far as my
>> > hardware is concerned. So if I am supposed to use it to work on camera
>> > stuff there is an obstacle.
>> >
>> > I started by copying my .config file over to the tree, and then running
>> > make oldconfig (as you said and as I would have done anyway).
>> >
>> > The problem seems to be centered right here (couple of lines
>> > from .config follow)
>> >
>> > CONFIG_DRM_RADEON=m
>> > # CONFIG_DRM_RADEON_KMS is not set
>> >
>> > I have a Radeon video card, obviously. Specifically, it is (extract from X
>> > config file follows)
>> >
>> > # Device configured by xorgconfig:
>> >
>> > Section "Device"
>> >    Identifier  "ATI Radeon HD 3200"
>> >    Driver      "radeon"
>> >
>> > Now, what happens is that with the kernel configuration (see above) I
>> > cannot start X in the -rc kernel. I get bumped out with an error
>> > message (details below) whereas that _was_ my previous configuration
>> > setting.
>> >
>> > But if in the config for the -rc kernel I change the second line by
>> > turning on CONFIG_DRM_RADEON_KMS the situation is even worse. Namely, the
>> > video cuts off during the boot process, with the monitor going blank and
>> > flashing up a message that it lost signal. After that the only thing to do
>> > is a hard reset, which strangely does not result in any check for a dirty
>> > file system, showing that things _really_ got screwed. These problems wit
>> > the video cutting off at boot are with booting into the _terminal_, BTW. I
>> > do not and never have made a practice of booting into X. I start X from
>> > the command line after boot. Thus, the video cutting off during boot has
>> > nothing to do with X at all, AFAICT.
>> >
>> > So as I said there are two alternatives, both of them quite unpleasant.
>> >
>> > Here is what the crash message is on the screen from the attempt to start
>> > up X, followed by what seem to be the relevant lines from the log file,
>> > with slightly more detail.
>> >
>> > Markers: (--) probed, (**) from config file, (==) default setting,
>> >        (++) from command line, (!!) notice, (II) informational,
>> >        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
>> > (==) Log file: "/var/log/Xorg.0.log", Time: Sun Dec 19 14:32:12 2010
>> > (==) Using config file: "/etc/X11/xorg.conf"
>> > (==) Using system config directory "/usr/share/X11/xorg.conf.d"
>> > (II) [KMS] drm report modesetting isn't supported.
>> > (EE) RADEON(0): Unable to map MMIO aperture. Invalid argument (22)
>> > (EE) RADEON(0): Memory map the MMIO region failed
>> > (EE) Screen(s) found, but none have a usable configuration.
>> >
>> > Fatal server error:
>> > no screens found
>> >
>> > Please consult the The X.Org Foundation support
>> >         at http://wiki.x.org
>> >  for help.
>> > Please also check the log file at "/var/log/Xorg.0.log" for additional
>> > information.
>> >
>> > xinit: giving up
>> > xinit: unable to connect to X server: Connection refused
>> > xinit: server error
>> > xinit: unable to connect to X server: Connection refused
>> > xinit: server error
>> > kilgota@khayyam:~$
>> >
>> > And the following, too, from the log file, which perhaps contains one or
>> > two
>> > more details:
>> >
>> > [    48.050] (--) using VT number 7
>> >
>> > [    48.052] (II) [KMS] drm report modesetting isn't supported.
>> > [    48.052] (II) RADEON(0): TOTO SAYS 00000000feaf0000
>> > [    48.052] (II) RADEON(0): MMIO registers at 0x00000000feaf0000: size
>> > 64KB
>> > [    48.052] (EE) RADEON(0): Unable to map MMIO aperture. Invalid argument
>> > (22)
>> > [    48.052] (EE) RADEON(0): Memory map the MMIO region failed
>> > [    48.052] (II) UnloadModule: "radeon"
>> > [    48.052] (EE) Screen(s) found, but none have a usable configuration.
>> > [    48.052]
>> > Fatal server error:
>> > [    48.052] no screens found
>> > [    48.052]
>> >
>> > There are a couple of suggestions about things to try, such as compiling
>> > with CONFIG_DRM_RADEON_KMS and then passing the parameter modeset=0 to the
>> > radeon module. But that does not seem to help, either.
>> >
>> > The help screens in make menuconfig do not seem to praise the
>> > CONFIG_DRM_RADEON_KMS very highly, and seem to indicate that this is still
>> > a very experimental feature.
>> >
>> > There are no such equivalent problems with my current kernel, which is a
>> > home-compiled 2.6.35.7.
>> >
>> > I realize that this is a done decision, but it is exactly this kind of
>> > thing that I had in mind when we had the Great Debate on the linux-media
>> > list about whether to use hg or git. My position was to let hardware
>> > support people to run hg with the compatibility layer for recent kernels
>> > (and 2.6.35.7 is certainly recent!). Well, the people who had such a
>> > position did not win. So now here is unfortunately the foreseeable result.
>> > An experimental kernel with some totally unrelated bug which affects my
>> > hardware and meanwhile stops all progress.
>>
>> If you enable radeon KMS, you need to enable fbcon in your kernel or
>> you will lose video when the radeon kms driver loads since it controls
>> the video device and provide a legacy kernel fbdev interface.  As for
>> X, you need a ddx (xf86-video-ati) built with kms support (6.13.x
>> series).
>>
>> Alex
>
> OK, I will try to pursue this. But, first to be clear about the sequence
> of events:
>
> In my previous setup using 2.6.35.7 the radeon KMS was *not* enabled and
> things worked just fine. When I ran through "make oldconfig" I did not
> change that (see above). Then I was able to boot, but not able to start
> and X session.
>
> After rebooting with my old kernel, I did some searching for the error
> messages that I got (again, see above) and tried to follow the suggestion
> of turning that KMS config option on, experimenting with various things
> such as passing an option to the module to disable the KMS when loading.
> But with the KMS config option things were even worse than without it, in
> that I could not even boot the machine.
>
> So I am glad to let things remain as they were and not to use this
> new-fangled option. Therefore one rather meaningful question is, why did
> things not continue to work when I did not change anything about my
> configuration?
>
> Now, as to which version of the X drivers that I am running, it does not
> seem to be a problem:
>
> kilgota@khayyam:~/slackware64-current/slackware64/x$ ls | grep ati
> [...]
> xf86-video-ati-6.13.2-x86_64-1.txt
> xf86-video-ati-6.13.2-x86_64-1.txz
> xf86-video-ati-6.13.2-x86_64-1.txz.asc
> kilgota@khayyam:~/slackware64-current/slackware64/x$
>

IIRC, slackware does not handle KMS properly.

Alex

> and
>
> kilgota@khayyam:/var/log/packages$ ls | grep ati
> [...]
> xf86-video-ati-6.13.2-x86_64-1
> kilgota@khayyam:/var/log/packages$
>
> As to
>
>> If you enable radeon KMS, you need to enable fbcon in your kernel or
>> you will lose video when the radeon kms driver loads since it controls
>> the video device and provide a legacy kernel fbdev interface.
>
> Again, thanks for the suggestions. I will see what happens if I put in the
> framebuffer console option. I am sure it is not there; I have otherwise
> not particularly enjoyed using it and have usually tried to avoid its use.
> It requires still another option: to use a font which is large enough. I
> cannot use a console with some kind of 8x8 or 4x6 font, or whatever. So to
> hunt for a good font is already extra trouble for nothing. But also when
> the framebuffer console kicks in the bootup messages disappear in the
> middle of the boot procedure. Thanks, I would much rather see what is
> happening than to look at pretty pictures while booting or to have the
> messages go into a black hole halfway through. Some of us are just a
> little bit old-fashioned that way and really do not give a hoot whether
> the bootup looks sexy or not. In other words, I find myself confronted
> with one of those situations where not all movement is progress.
>
> Thus, again, why did things collapse now and refuse to work properly
> without the KMS option, when without the KMS option things worked
> perfectly well in 2.6.35.7 ? Judging from what the error messages are
> saying, it appears to me that in the presence of the new kernel
> there seems to be an attempt to use the KMS option regardless of
> whether it is present, and when it is not present one is bumped out with
> an "error" which in the previous environment was no error at all. Weird.
>
> Theodore Kilgore
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