Commit c962a78f authored by Emil Velikov's avatar Emil Velikov Committed by Emil Velikov
Browse files

vulkan/wsi: check if the display_fd given is master

As effectively required by the extension, we need to ensure we're master

Currently drivers employ vendor specific solutions, which check if the
device behind the fd is capable*, yet none of them do the master check.

*In the radv case, if acceleration is available.

Instead of duplicating the check in each driver, keep it where it's
needed and used.

Note this copies libdrm's drmIsMaster() to avoid depending on bleeding
edge version of the library.

v2: set the fd to -1 if not master (Bas)

Fixes: da997ebe

 ("vulkan: Add KHR_display extension using DRM [v10]")
Cc: Andres Rodriguez <>
Cc: Jason Ekstrand <>
Cc: Keith Packard <>
Reported-by: Andres Rodriguez's avatarAndres Rodriguez <>
Reviewed-by: Bas Nieuwenhuizen's avatarBas Nieuwenhuizen <>
Signed-off-by: Emil Velikov's avatarEmil Velikov <>
parent 1a9367c1
......@@ -1812,6 +1812,30 @@ fail_attr_init:
return ret;
* Local version fo the libdrm helper. Added to avoid depending on bleeding
* edge version of the library.
static int
local_drmIsMaster(int fd)
/* Detect master by attempting something that requires master.
* Authenticating magic tokens requires master and 0 is an
* internal kernel detail which we could use. Attempting this on
* a master fd would fail therefore fail with EINVAL because 0
* is invalid.
* A non-master fd will fail with EACCES, as the kernel checks
* for master before attempting to do anything else.
* Since we don't want to leak implementation details, use
return drmAuthMagic(fd, 0) != -EACCES;
wsi_display_init_wsi(struct wsi_device *wsi_device,
const VkAllocationCallbacks *alloc,
......@@ -1827,6 +1851,9 @@ wsi_display_init_wsi(struct wsi_device *wsi_device,
wsi->fd = display_fd;
if (wsi->fd != -1 && !local_drmIsMaster(wsi->fd))
wsi->fd = -1;
wsi->alloc = alloc;
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