Re: Blank screen at startup (conflict with VESA VGA)

[Aaron Plattner <aplattner-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On Tue, Apr 13, 2010 at 04:34:51AM -0700, Marcin Slusarz wrote:
> On Tue, Apr 13, 2010 at 11:15:28AM +1000, Christopher James Halse Rogers wrote:
> > On Mon, 2010-04-12 at 20:04 +0300, Pekka Paalanen wrote:
> > > On Mon, 12 Apr 2010 12:50:13 +0200
> > > Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > 
> > > > I'm not aware of any trick to make both nv and nouveau working.
> > > > Maybe there should be a way to prevent nv (and vesa, but not
> > > > fbdev) from loading when KMS is in use?
> > > 
> > > Yeah, there was a brief discussion about that recently:
> > > http://people.freedesktop.org/~cbrill/dri-log/index.php?date=2010-03-21&channel=nouveau&show_html=true&highlight_names=&update=Update&date=2010-03-21
> > > 
> > > I haven't heard anything about it since.
> > > 
> > 
> > I wrote a patch for vesa on bugzilla[1] to do exactly that; a similar
> > one for nv wouldn't be hard.
> > 
> > [1] https://bugs.freedesktop.org/show_bug.cgi?id=26878
> 
> Yay, thanks.
> I adapted it to xf86-video-nv and it works!
> Now we need to trick Aaron to apply it.
> 
> Aaron: please, please, please apply.
> :)

Sorry for the slow reply.  It sucks that this is necessary, but I guess it
makes sense.  Comments below.

> ---
> From 112a8c9aa9de6ea30b4c3c98e5d7cbce312aaaf8 Mon Sep 17 00:00:00 2001
> From: Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Date: Tue, 13 Apr 2010 13:17:56 +0200
> Subject: [PATCH] Refuse to bind to a device which has kernel modesetting active.
> 
> Touching directly the hardware while kernel modesetting is active
> breaks console output.
> 
> Patch almost entrirely based on VESA patch by
> Christopher James Halse Rogers <christopher.halse.rogers-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
> 
> Signed-off-by: Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  configure.ac    |   11 +++++++++++
>  src/Makefile.am |    2 +-
>  src/nv_driver.c |   33 +++++++++++++++++++++++++++++++++
>  3 files changed, 45 insertions(+), 1 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index d717805..3028005 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -134,6 +134,17 @@ AC_SUBST([modes_dir])
>  AC_SUBST([XORG_CFLAGS])
>  AC_SUBST([moduledir])
>  
> +if test "x$XSERVER_LIBPCIACCESS" = xyes; then
> +    PKG_CHECK_MODULES(LIBDRM, [libdrm > 2.4.3 xf86driproto], HAVE_KMS="yes", HAVE_KMS="no")
> +    if test "x$HAVE_KMS" = xyes; then
> +        AC_DEFINE(HAVE_KMS, 1, [Have kernel modesetting])
> +    else
> +        AC_MSG_WARN(Support for detecting kernel modesetting drivers is not available.)
> +        AC_MSG_WARN(This driver can cause display problems in the presence of kernel modesetting.)
> +        AC_MSG_WARN(Please install libdrm > 2.4.3 and xf86driproto to enable kms detection.)

s/kms/KMS/

> +    fi
> +fi
> +
>  DRIVER_NAME=nv
>  AC_SUBST([DRIVER_NAME])
>  
> diff --git a/src/Makefile.am b/src/Makefile.am
> index 2677d9c..5d57010 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -23,7 +23,7 @@
>  # -avoid-version prevents gratuitous .0.0.0 version numbers on the end
>  # _ladir passes a dummy rpath to libtool so the thing will actually link
>  # TODO: -nostdlib/-Bstatic/-lgcc platform magic, not installing the .a, etc.
> -AM_CFLAGS = @XMODES_CFLAGS@ @XORG_CFLAGS@
> +AM_CFLAGS = @XMODES_CFLAGS@ @XORG_CFLAGS@ $(LIBDRM_CFLAGS)
>  nv_drv_la_LTLIBRARIES = nv_drv.la
>  nv_drv_la_LDFLAGS = -module -avoid-version
>  nv_drv_ladir = @moduledir@/drivers
> diff --git a/src/nv_driver.c b/src/nv_driver.c
> index 0d017f9..e117626 100644
> --- a/src/nv_driver.c
> +++ b/src/nv_driver.c
> @@ -33,6 +33,11 @@
>  #include "xf86int10.h"
>  #include "vbeModes.h"
>  
> +#ifdef HAVE_KMS
> +#include <xf86drmMode.h>
> +#include <dri.h>
> +#endif
> +
>  const   OptionInfoRec * RivaAvailableOptions(int chipid, int busid);
>  Bool    RivaGetScrnInfoRec(PciChipsets *chips, int chip);
>  Bool    G80GetScrnInfoRec(PciChipsets *chips, int chip);
> @@ -830,6 +835,26 @@ NVIsSupported(CARD32 id)
>      return FALSE;
>  }
>  
> +#ifdef HAVE_KMS
> +static Bool NVKernelModesettingEnabled (struct pci_device *device)
> +{
> +    char *busIdString;
> +    int ret;
> +
> +    if (!xf86LoaderCheckSymbol("DRICreatePCIBusID"))
> +	return FALSE;

I know the rest of the code uses tabs, but please use spaces for new code.

> +
> +    busIdString = DRICreatePCIBusID(device);

Eww.  Why doesn't drmCheckModesettingSupported take a pci_device*?  Oh
well, whatever.

> +    ret = drmCheckModesettingSupported(busIdString);

There's no chance of false positives here, right?  E.g. if you set
nouveau.modeset=0 on the kernel command line, does that make this return
nonzero?

> +    xfree(busIdString);
> +
> +    return (ret == 0);
> +}
> +#else
> +static inline Bool NVKernelModesettingEnabled (struct pci_device *device) { return FALSE; }
> +#endif //HAVE_KMS
> +
>  /* Mandatory */
>  #if XSERVER_LIBPCIACCESS
>  static Bool
> @@ -864,6 +889,14 @@ NVPciProbe(DriverPtr drv, int entity, struct pci_device *dev, intptr_t data)
>                 NV_NAME ": Found NVIDIA %s at %2.2x@%2.2x:%2.2x:%1.1x\n",
>                 name, dev->bus, dev->domain, dev->dev, dev->func);
>  
> +    /* Trying to bring up a NV mode while kernel modesetting is enabled
> +       results in badness */
> +    if (NVKernelModesettingEnabled (dev)) {
> +	xf86Msg (X_ERROR,
> +	         "NV: Kernel modesetting driver in use, refusing to load\n");

Please use NV_NAME instead of hard-coding the "NV:" prefix.

> +	return FALSE;
> +    }
> +
>      if(NVIsG80(id))
>          return G80GetScrnInfoRec(NULL, entity);
>      else if(dev->vendor_id == PCI_VENDOR_NVIDIA_SGS)
> -- 
> 1.7.0.4