Re: X / wscons broken with serial console

[Matthieu Herrb]

On Thu, Apr 21, 2016 at 02:39:32PM +0200, Matthieu Herrb wrote:
> On Thu, Apr 21, 2016 at 01:22:40PM +0100, Stuart Henderson wrote:
> > If the bootloader sets up a serial console, I can no longer get X to
> > start:
> > 
> > [   138.658] (--) checkDevMem: using aperture driver /dev/xf86
> > [   138.738] (EE) 
> > Fatal server error:
> > [   138.738] (EE) xf86OpenConsole: No console driver found
> >     Supported drivers: wscons
> >     Check your kernel's console driver configuration and /dev entries(EE) 
> > [   138.738] (EE) 
> > Please consult the The X.Org Foundation support 
> >      at http://wiki.x.org
> >  for help. 
> > [   138.738] (EE) Please also check the log file at "/var/log/Xorg.0.log" 
> > for additional information.
> > [   138.738] (EE) 
> > [   138.739] (EE) Server terminated with error (1). Closing log file.
> > 
> > Any ideas what it was that might have broken this?
> 
> Very probably the switch to native WSCONS support in the X server, and
> more precisely the fact that the X server now uses sysctl to figure
> out what is the console device to open.
> 
> I need to tink a bit on a good solution... 
>

This diff should fix the problem by testing if the console device is a
wsdisplay(4) device and falling back to /dev/ttyCn otherwise. I've
changed the logic a bit in the hope to make the code more readable,
but it's still a bit of a mess.

I don't know if we need to add a knob to explicitely set the path of
the device to use for X.

Index: bsd_init.c
===================================================================
RCS file: /cvs/OpenBSD/xenocara/xserver/hw/xfree86/os-support/bsd/bsd_init.c,v
retrieving revision 1.18
diff -u -p -u -r1.18 bsd_init.c
--- bsd_init.c  2 Apr 2016 14:25:10 -0000       1.18
+++ bsd_init.c  21 Apr 2016 19:55:19 -0000
@@ -611,17 +611,27 @@ xf86OpenWScons(void)
     if (xf86Info.ShareVTs)
         FatalError("-sharevt is not supported with wscons\n");
 
+    /* default value if probing the console device fails */
+    snprintf(vtprefix, sizeof(vtprefix), "/dev/ttyC");
+
+    /* probe console device - it my be /dev/ttyD0 on some multi-heads setups */
     mib[0] = CTL_KERN;
     mib[1] = KERN_CONSDEV;
     len = sizeof(dev);
     if (sysctl(mib, 2, &dev, &len, NULL, 0) != -1) {
-        snprintf(vtprefix, sizeof(vtprefix), "/dev/%s", devname(dev, S_IFCHR));
-        /* strip number, assuming 0 */
-        p = strchr(vtprefix, '0');
-        *p = '\0';
-    } else
-        snprintf(vtprefix, sizeof(vtprefix), "/dev/ttyC");
-
+        snprintf(vtname, sizeof(vtname), "/dev/%s", devname(dev, S_IFCHR));
+       if ((fd = open(vtname, O_RDWR)) != -1) {
+           if (ioctl(fd, WSDISPLAYIO_GTYPE, &i) == 0) {
+                /* console is a wsdisplay(4) device */
+                strlcpy(vtprefix, vtname, sizeof(vtprefix));
+                /* strip number, assuming 0 */
+                p = strchr(vtprefix, '0');
+                *p = '\0';
+               close(fd);
+               fd = -1;
+           }
+       }
+    }
     if (VTnum != -1) {
         snprintf(vtname, sizeof(vtname), "%s%01x", vtprefix, VTnum - 1);
         xf86Info.vtno = VTnum;

-- 
Matthieu Herrb

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