2012/6/12 David Airlie airlied@redhat.com:

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From: "Rafał Miłecki" zajec5@gmail.com To: xorg-devel@lists.x.org, "dri-devel" dri-devel@lists.freedesktop.org, "Dave Airlie" airlied@redhat.com Cc: "Alex Deucher" alexdeucher@gmail.com Sent: Monday, 11 June, 2012 8:55:56 PM Subject: Re: No screens after (WW) Falling back to old probe method for modesetting

2012/6/11 Rafał Miłecki zajec5@gmail.com:

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I'm trying to switch from fbdev to modesetting for my AMD Southern Islands VERDE card. Of course I've KMS running just fine, radeon module loads and sets correct resolution, dmesg looks alright

Unfortunately Xorg doesn't start after forcing "modesetting", AFAIU the driver doesn't provide any screens/modes. It looks like this: (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so (WW) Falling back to old probe method for modesetting (II) UnloadModule: "modesetting" (II) Unloading modesetting (EE) Screen(s) found, but none have a usable configuration.

Can you give me any tip on this? My X.Org X Server is 1.10.4, I'm using xf86-video-modesetting from today's git. Any patch/trick to debug this issue?

Attaching Xorg.0.logs

Try adding a BusID maybe, though I'm not sure how tested modesetting is with that old an X server.

I already have it added. It's weird modesetting doesn't put any message in Xorg.0.log, it has few messages printing in source. Will put some debugging in modesetting to see what actually happens.

2012/6/12 Rafał Miłecki zajec5@gmail.com:

2012/6/11 Rafał Miłecki zajec5@gmail.com:

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I'm trying to switch from fbdev to modesetting for my AMD Southern Islands VERDE card. Of course I've KMS running just fine, radeon module loads and sets correct resolution, dmesg looks alright

Unfortunately Xorg doesn't start after forcing "modesetting", AFAIU the driver doesn't provide any screens/modes. It looks like this: (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so (WW) Falling back to old probe method for modesetting (II) UnloadModule: "modesetting" (II) Unloading modesetting (EE) Screen(s) found, but none have a usable configuration.

Can you give me any tip on this? My X.Org X Server is 1.10.4, I'm using xf86-video-modesetting from today's git. Any patch/trick to debug this issue?

I don't think old X server is an issue here. The function to focus on is probe_hw_pci.

This function calls "open_hw" which opens /dev/dri/card0 and return fd (9 in my case, irrelevant). Then comes the moment when probe_hw_pci calls: id = drmGetBusid(fd); devid = ms_DRICreatePCIBusID(pdev);

The first one returns NULL, the second one returns "pci:0000:03:00.0". As the "id" is NULL (empty string) probe_hw_pci returns false and the rest fails.

I can't say why drmGetBusid returns NULL. My drm is from yesterday's git and DRM_IOCTL_GET_UNIQUE isn't something bleeding edge AFAIK. Hacking probe_hw_pci to return TRUE allows me start X with modesetting.

I've hacked xf86drm.c::drmGetBusid to print some debugging messages.

When we call "drmGetBusid" in "probe_hw_pci", u.unique_len gets 0 and u.unique gets "\0".

However I've noticed there's one more call to "drmGetBusid". The stacktrace is: PreInit → drmOpen(NULL, BusID) → drmOpenByBusid → drmGetBusid In the above call, drmGetBusid gets u.unique_len gets 16 and u.unique gets "pci:0000:03:00.0\0".

Does it give you any hint what can happen here?