xserver: Branch 'master'

[GitLab Mirror]

 config/udev.c |   31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

New commits:
commit 2f53d1cf7304574a516f6868822307648bc35333
Author: Povilas Kanapickas <povilas at radix.lt>
Date:   Wed Apr 7 18:22:05 2021 +0300

    config: Fix platform busid parsing when there is no ID_PATH prop
    
    On at least Lenovo Thinkpad E585 udev does not have ID_PATH property for
    the drm node (see
    https://gitlab.freedesktop.org/xorg/xserver/-/issues/993). While this is
    likely udev bug, this causes the device to be not recognized as
    attribs->busid is NULL, which causes platform_find_pci_info to be not
    called and corresponding xf86_platform_devices[i]->pdev to be NULL.
    
    At this moment pdev being NULL will cause a crash, but this is a
    different bug.
    
    Fixes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/993
    Fixes: 0816e8fc linux: Make platform device probe less fragile
    Reviewed-by: Zoltán Böszörményi <zboszor at gmail.com>
    Signed-off-by: Povilas Kanapickas <povilas at radix.lt>

diff --git a/config/udev.c b/config/udev.c
index 411a459f4..836fc2afa 100644
--- a/config/udev.c
+++ b/config/udev.c
@@ -502,6 +502,34 @@ static char *strrstr(const char *haystack, const char *needle)
     return last;
 }
 
+/* For certain devices udev does not create ID_PATH entry (which is presumably a bug
+ * in udev). We work around that by implementing a minimal ID_PATH calculator
+ * ourselves along the same logic that udev uses. This works only for the case of
+ * a PCI device being directly connected to a PCI bus, but it will cover most end
+ * users with e.g. a new laptop which only has beta hardware driver support.
+ * See https://gitlab.freedesktop.org/xorg/xserver/-/issues/993 */
+static char*
+config_udev_get_fallback_bus_id(struct udev_device *udev_device)
+{
+    const char *sysname;
+    char *busid;
+
+    udev_device = udev_device_get_parent(udev_device);
+    if (udev_device == NULL)
+        return NULL;
+
+    if (strcmp(udev_device_get_subsystem(udev_device), "pci") != 0)
+        return NULL;
+
+    sysname = udev_device_get_sysname(udev_device);
+    busid = XNFalloc(strlen(sysname) + 5);
+    busid[0] = '\0';
+    strcat(busid, "pci:");
+    strcat(busid, sysname);
+
+    return busid;
+}
+
 static void
 config_udev_odev_setup_attribs(struct udev_device *udev_device, const char *path, const char *syspath,
                                int major, int minor,
@@ -526,6 +554,9 @@ config_udev_odev_setup_attribs(struct udev_device *udev_device, const char *path
         attribs->busid[3] = ':';
     }
 
+    if (!value)
+        attribs->busid = config_udev_get_fallback_bus_id(udev_device);
+
     /* ownership of attribs is passed to probe layer */
     probe_callback(attribs);
 }