From c0b2e69f8815881d51b68b4f73e6c7f8cc2417a1 Mon Sep 17 00:00:00 2001
From: Franck Bui <fbui@suse.com>
Date: Thu, 1 Jul 2021 12:30:29 +0200
Subject: [PATCH] login: XGI Z7/Z9 (XG20 core) graphic chip requires
 master-of-seat to be set

This graphic chip doesn't have a DRM driver and fall back to vesa-framebuffer
driver.

Without this patch, users of such chip suddenly see their GUI broken without
any indication or reason of what happened (no error message). Hence this
regression is near to impossible to troubleshoot for end users. Such case was
reported https://bugzilla.opensuse.org/show_bug.cgi?id=1187154.

Rather than adding another exception in the udev rules to deal with such
HWs, they instead get their own hwdb file '60-seat.hwdb'.
---
 hwdb.d/60-seat.hwdb        | 20 ++++++++++++++++++++
 hwdb.d/meson.build         |  1 +
 hwdb.d/parse_hwdb.py       |  2 ++
 src/login/71-seat.rules.in |  5 +++++
 4 files changed, 28 insertions(+)
 create mode 100644 hwdb.d/60-seat.hwdb

diff --git a/hwdb.d/60-seat.hwdb b/hwdb.d/60-seat.hwdb
new file mode 100644
index 00000000000..d280040c8a3
--- /dev/null
+++ b/hwdb.d/60-seat.hwdb
@@ -0,0 +1,20 @@
+# This file is part of systemd.
+#
+# This file lists graphic devices that don't have a DRM driver and fall back to
+# a frame-buffer one instead. Since commit 6260d28b8a, frame-buffer devices are
+# no more considered as graphical capable.
+#
+# The matches have the 'fb' prefix to make sure that only the framebuffer
+# device, and not the (parent) PCI device, is tagged with 'master-of-seat'.
+#
+# Allowed properties are:
+#    ID_TAG_MASTER_OF_SEAT=1
+
+#########################################
+# eXtreme Graphic Innovation (XGI)
+#########################################
+
+# Z7/Z9 (XG20 core), a rather ancient graphic chip, doesn't have a DRM driver
+# and falls back to vesafb.
+fb:pci:v000018CAd00000020*
+ ID_TAG_MASTER_OF_SEAT=1
diff --git a/hwdb.d/meson.build b/hwdb.d/meson.build
index fd8c15a521d..0a96b5553a5 100644
--- a/hwdb.d/meson.build
+++ b/hwdb.d/meson.build
@@ -25,6 +25,7 @@ hwdb_files_test = files('''
         60-evdev.hwdb
         60-input-id.hwdb
         60-keyboard.hwdb
+        60-seat.hwdb
         60-sensor.hwdb
         70-joystick.hwdb
         70-mouse.hwdb
diff --git a/hwdb.d/parse_hwdb.py b/hwdb.d/parse_hwdb.py
index 6d88766f0b2..3cd4b486a6b 100755
--- a/hwdb.d/parse_hwdb.py
+++ b/hwdb.d/parse_hwdb.py
@@ -67,6 +67,7 @@ UDEV_TAG = Word(string.ascii_uppercase, alphanums + '_')
 # Those patterns are used in type-specific matches
 TYPES = {'mouse':    ('usb', 'bluetooth', 'ps2', '*'),
          'evdev':    ('name', 'atkbd', 'input'),
+         'fb':       ('pci'),
          'id-input': ('modalias'),
          'touchpad': ('i8042', 'rmi', 'bluetooth', 'usb'),
          'joystick': ('i8042', 'rmi', 'bluetooth', 'usb'),
@@ -163,6 +164,7 @@ def property_grammar():
              ('IEEE1394_UNIT_FUNCTION_VIDEO', Or((Literal('0'), Literal('1')))),
              ('ID_VENDOR_FROM_DATABASE', name_literal),
              ('ID_MODEL_FROM_DATABASE', name_literal),
+             ('ID_TAG_MASTER_OF_SEAT', Literal('1')),
             )
     fixed_props = [Literal(name)('NAME') - Suppress('=') - val('VALUE')
                    for name, val in props]
diff --git a/src/login/71-seat.rules.in b/src/login/71-seat.rules.in
index 809467c6c85..0ebbb8efe2e 100644
--- a/src/login/71-seat.rules.in
+++ b/src/login/71-seat.rules.in
@@ -29,6 +29,11 @@ SUBSYSTEM=="graphics", KERNEL=="fb[0-9]", IMPORT{cmdline}="nomodeset", TAG+="mas
 SUBSYSTEM=="pci", ENV{ID_PCI_CLASS_FROM_DATABASE}=="Display controller", \
                   ENV{DRIVER}=="", IMPORT{cmdline}="nomodeset", TAG+="seat", TAG+="master-of-seat"
 
+# Synthesize a seat for graphic devices without DRM and that fall back to fb
+# device instead. Such HWs are listed in hwdb.
+SUBSYSTEM=="graphics", KERNEL=="fb[0-9]*", ATTRS{modalias}=="?*", IMPORT{builtin}="hwdb fb:$attr{modalias}"
+ENV{ID_TAG_MASTER_OF_SEAT}=="1", TAG+="master-of-seat"
+
 SUBSYSTEM=="drm", KERNEL=="card[0-9]*", TAG+="seat", TAG+="master-of-seat"
 
 # Allow individual USB ports to be assigned to a seat