Patch 6/6 modesetting: try to get gpu device fd from seatd arbiter

The device node with seatd like with systemd-logind are opened during probe
(see get_drm_info in hw/xfree86/os-support/shared/drm_platform.c),
but in case of failure, the modesetting driver tries to open device
node directly (open_hw function in modesetting/driver.c).

This patch aligns functionality and as last resort ask's seatd arbiter
to open device for us.

To make it functional seatd_libseat_controls_session, seatd_libseat_open_graphics needs _X_EXPORT

Signed-off-By: Tautvis <[email protected]>

Author: cepelinas9000

hw/xfree86/common/seatd-libseat.h

@@ -31,11 +31,11 @@
 #include <xf86Xinput.h>
 extern int seatd_libseat_init(BOOL KeepTty_state);
 extern void seatd_libseat_fini(void);
-extern int seatd_libseat_open_graphics(const char *path);
+extern _X_EXPORT int seatd_libseat_open_graphics(const char *path);
 extern void seatd_libseat_open_device(InputInfoPtr p,int *fd,Bool *paus);
 extern void seatd_libseat_close_device(InputInfoPtr p);
 extern int seatd_libseat_switch_session(int session);
-extern Bool seatd_libseat_controls_session(void);
+extern _X_EXPORT Bool seatd_libseat_controls_session(void);
 #else
 
 static inline int seatd_libseat_init(BOOL KeepTty_state) {(void)KeepTty_state; return -1; };

hw/xfree86/drivers/video/modesetting/driver.c

@@ -70,6 +70,11 @@
 #ifdef XSERVER_LIBPCIACCESS
 #include <pciaccess.h>
 #endif
+
+#ifdef SEATD_LIBSEAT
+#include "seatd-libseat.h"
+#endif
+
 #include "driver.h"
 
 static void AdjustFrame(ScrnInfoPtr pScrn, int x, int y);
@@ -238,6 +243,8 @@ open_hw(const char *dev)
     if ((fd = get_passed_fd()) != -1)
         return fd;
 
+
+
     if (dev)
         fd = open(dev, O_RDWR | O_CLOEXEC, 0);
     else {
@@ -247,6 +254,31 @@ open_hw(const char *dev)
             fd = open(dev, O_RDWR | O_CLOEXEC, 0);
         }
     }
+
+#ifdef SEATD_LIBSEAT
+    /* try get device from seatd arbiter */
+    if (fd == -1 && seatd_libseat_controls_session()){
+        if (dev){
+            fd = seatd_libseat_open_graphics(dev);
+            if (fd != -1){
+                return fd;
+            }
+
+        } else {
+            const char *dev_env = getenv("KMSDEVICE");
+            if (dev_env == NULL){
+                dev_env = "/dev/dri/card0";
+            }
+
+            fd = seatd_libseat_open_graphics(dev_env);
+
+            if (fd != -1) {
+                return fd;
+            }
+        }
+    }
+#endif
+
     if (fd == -1)
         xf86DrvMsg(-1, X_ERROR, "open %s: %s\n", dev, strerror(errno));