[PATCH] Refuse to bind to a device which has kernel modesetting active.

[Marcin Slusarz]

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 at canonical.com>

Signed-off-by: Marcin Slusarz <marcin.slusarz at gmail.com>
---
 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.)
+    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;
+
+    busIdString = DRICreatePCIBusID(device);
+
+    ret = drmCheckModesettingSupported(busIdString);
+    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");
+	return FALSE;
+    }
+
     if(NVIsG80(id))
         return G80GetScrnInfoRec(NULL, entity);
     else if(dev->vendor_id == PCI_VENDOR_NVIDIA_SGS)
-- 
1.7.0.4