From c647df3e017a1a61b57ca83c210e27d1a1479f2a Mon Sep 17 00:00:00 2001
From: Alexei Colin <ac@alexeicolin.com>
Date: Fri, 26 Dec 2014 23:15:28 -0500
Subject: [PATCH 2/2] xfree86: systemd-logind and pre-SUPPORTS_SERVER_FD
 drivers

Drivers that without SUPPORTS_SERVER_FD (e.g. armsoc) *and*
without 'platformProbe' method (only with legacy 'Probe'
method)  are denied access to the DRM device while the server
holds a file descriptor to the device obtained from
systemd-logind. The driver's requests that require the
'master' privilege are denied by kernel drm module because
systemd-logind sets its file object to be the master upon
opening it.

The server acquires file descriptors without regard to
the SUPPORTS_SERVER_FD capability of the driver during
bus probing. The code to release these file descriptors
for drivers without SUPPORTS_SERVER_FD was already present,
but only for drivers with platformProbe method. This
commits move this code up the stack so that it takes effect
for both kinds of drivers.
---
 hw/xfree86/common/xf86Bus.c         |  2 ++
 hw/xfree86/common/xf86platformBus.c | 35 ++++++++++++++++++++++++++++-------
 hw/xfree86/common/xf86platformBus.h |  1 +
 3 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/hw/xfree86/common/xf86Bus.c b/hw/xfree86/common/xf86Bus.c
index 889294f..dc68755 100644
--- a/hw/xfree86/common/xf86Bus.c
+++ b/hw/xfree86/common/xf86Bus.c
@@ -78,6 +78,8 @@ xf86CallDriverProbe(DriverPtr drv, Bool detect_only)
     Bool foundScreen = FALSE;
 
 #ifdef XSERVER_PLATFORM_BUS
+    xf86platformReleaseDriverFDs(drv);
+
     if (drv->platformProbe != NULL) {
         foundScreen = xf86platformProbeDev(drv);
     }
diff --git a/hw/xfree86/common/xf86platformBus.c b/hw/xfree86/common/xf86platformBus.c
index 336305c..2b13cca 100644
--- a/hw/xfree86/common/xf86platformBus.c
+++ b/hw/xfree86/common/xf86platformBus.c
@@ -394,13 +394,6 @@ static Bool doPlatformProbe(struct xf86_platform_device *dev, DriverPtr drvp,
         }
     }
     if (entity != -1) {
-        if ((dev->flags & XF86_PDEV_SERVER_FD) && (!drvp->driverFunc ||
-                !drvp->driverFunc(NULL, SUPPORTS_SERVER_FDS, NULL))) {
-            systemd_logind_release_fd(dev->attribs->major, dev->attribs->minor, dev->attribs->fd);
-            dev->attribs->fd = -1;
-            dev->flags &= ~XF86_PDEV_SERVER_FD;
-        }
-
         if (drvp->platformProbe(drvp, entity, flags, dev, match_data))
             foundScreen = TRUE;
         else
@@ -617,4 +610,32 @@ void xf86platformPrimary(void)
         }
     }
 }
+
+/* Release file descriptors for devices that belong to drivers without
+ * SUPPORTS_SERVER_FD support. The server might be holding file
+ * descriptors acquired through systemd-logind during bus probing,
+ * without regard to whether the driver supports server-managed FDs.
+ */
+void xf86platformReleaseDriverFDs(DriverPtr drvp)
+{
+    GDevPtr *devList;
+    const unsigned numDevs = xf86MatchDevice(drvp->driverName, &devList);
+    int i;
+    struct xf86_platform_device *dev;
+
+    for (i = 0; i < numDevs; i++) {
+        dev = xf86_find_platform_device_by_busid(devList[i]->busID);
+        if (!dev)
+             continue;
+
+        if ((dev->flags & XF86_PDEV_SERVER_FD) && (!drvp->driverFunc ||
+                !drvp->driverFunc(NULL, SUPPORTS_SERVER_FDS, NULL)))
+	{
+	    systemd_logind_release_fd(dev->attribs->major, dev->attribs->minor,
+                                      dev->attribs->fd);
+	    dev->attribs->fd = -1;
+	    dev->flags &= ~XF86_PDEV_SERVER_FD;
+	}
+    }
+}
 #endif
diff --git a/hw/xfree86/common/xf86platformBus.h b/hw/xfree86/common/xf86platformBus.h
index 073051c..64c88ce 100644
--- a/hw/xfree86/common/xf86platformBus.h
+++ b/hw/xfree86/common/xf86platformBus.h
@@ -158,6 +158,7 @@ xf86PlatformMatchDriver(char *matches[], int nmatches);
 
 extern void xf86platformVTProbe(void);
 extern void xf86platformPrimary(void);
+extern void xf86platformReleaseDriverFDs(DriverPtr drvp);
 #endif
 
 #endif
-- 
2.2.1