libdrm: Fix PCI domain domain support

This works in conjunction with newer kernels. If we succeed in requesting
interface 1.4, the we know the kernel provides proper domain numbers. If
not, ignore the domain number as it's bogus (except on Alpha).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Adam Jackson <ajax@redhat.com>

1 files changed, 25 insertions, 5 deletions

diff --git a/xf86drm.c b/xf86drm.c
index 220aaa16..e48b9c99 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -229,7 +229,7 @@ drmHashEntry *drmGetEntry(int fd)
  * PCI:b:d:f format and the newer pci:oooo:bb:dd.f format.  In the format, o is
  * domain, b is bus, d is device, f is function.
  */
-static int drmMatchBusID(const char *id1, const char *id2)
+static int drmMatchBusID(const char *id1, const char *id2, int pci_domain_ok)
 {
     /* First, check if the IDs are exactly the same */
     if (strcasecmp(id1, id2) == 0)
@@ -257,6 +257,13 @@ static int drmMatchBusID(const char *id1, const char *id2)
                 return 0;
         }
 
+        /* If domains aren't properly supported by the kernel interface,
+         * just ignore them, which sucks less than picking a totally random
+         * card with "open by name"
+         */
+        if (!pci_domain_ok)
+                o1 = o2 = 0;
+
         if ((o1 != o2) || (b1 != b2) || (d1 != d2) || (f1 != f2))
             return 0;
         else
@@ -482,7 +489,7 @@ int drmAvailable(void)
  */
 static int drmOpenByBusid(const char *busid)
 {
-    int        i;
+    int        i, pci_domain_ok = 1;
     int        fd;
     const char *buf;
     drmSetVersion sv;
@@ -492,14 +499,27 @@ static int drmOpenByBusid(const char *busid)
         fd = drmOpenMinor(i, 1, DRM_NODE_RENDER);
         drmMsg("drmOpenByBusid: drmOpenMinor returns %d\n", fd);
         if (fd >= 0) {
+            /* We need to try for 1.4 first for proper PCI domain support
+             * and if that fails, we know the kernel is busted
+             */
             sv.drm_di_major = 1;
-            sv.drm_di_minor = 1;
+            sv.drm_di_minor = 4;
             sv.drm_dd_major = -1;       /* Don't care */
             sv.drm_dd_minor = -1;       /* Don't care */
-            drmSetInterfaceVersion(fd, &sv);
+            if (drmSetInterfaceVersion(fd, &sv)) {
+#ifndef __alpha__
+                pci_domain_ok = 0;
+#endif
+                sv.drm_di_major = 1;
+                sv.drm_di_minor = 1;
+                sv.drm_dd_major = -1;       /* Don't care */
+                sv.drm_dd_minor = -1;       /* Don't care */
+                drmMsg("drmOpenByBusid: Interface 1.4 failed, trying 1.1\n",fd);
+                drmSetInterfaceVersion(fd, &sv);
+            }
             buf = drmGetBusid(fd);
             drmMsg("drmOpenByBusid: drmGetBusid reports %s\n", buf);
-            if (buf && drmMatchBusID(buf, busid)) {
+            if (buf && drmMatchBusID(buf, busid, pci_domain_ok)) {
                 drmFreeBusid(buf);
                 return fd;
             }