untrusted comment: verify with openbsd-66-base.pub
RWSvK/c+cFe24Pkc+cMgTw3Vj3SReII6tSd6T0FaHUqqkQQ6FVn+AKlpUWcj6Xdq3ktR49eSMaq67C/SdXXMsJld44JciBm68Qg=

OpenBSD 6.6 errata 025, April 19, 2020:

Incorrect test for root in drm linux compatiblity code.

Apply by doing:
    signify -Vep /etc/signify/openbsd-66-base.pub -x 025_drm.patch.sig \
        -m - | (cd /usr/src && patch -p0)

And then rebuild and install a new kernel:
    KK=`sysctl -n kern.osversion | cut -d# -f1`
    cd /usr/src/sys/arch/`machine`/compile/$KK
    make obj
    make config
    make
    make install

Index: sys/dev/pci/drm/include/linux/capability.h
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/include/linux/capability.h,v
retrieving revision 1.1
diff -u -p -r1.1 capability.h
--- sys/dev/pci/drm/include/linux/capability.h	14 Apr 2019 10:14:53 -0000	1.1
+++ sys/dev/pci/drm/include/linux/capability.h	17 Apr 2020 06:32:00 -0000
@@ -13,7 +13,7 @@ static inline int 
 capable(int cap) 
 { 
 	KASSERT(cap == CAP_SYS_ADMIN);
-	return suser(curproc);
+	return suser(curproc) == 0;
 } 
 
 #endif