From 106b4a2a78b2a2f14885604891957b84bba502db Mon Sep 17 00:00:00 2001 From: Adrian Betschart Date: Fri, 11 Sep 2026 17:13:14 +0200 Subject: drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validation amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and uses the first encoding that validates. YCbCr 4:4:4 is listed before RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the "color format" property is left at AUTO, even though RGB fits the same link. That contradicts the documented AUTO behaviour for HDMI in enum drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when the bandwidth is not available or the mode is 4:2:0-only), which the amdgpu implementation of the property also describes. It also leaves the "Broadcast RGB" property without effect on such sinks, since the quantization range it selects only applies to RGB output. Try RGB first. The mask still holds every encoding the sink supports, so a mode that cannot carry RGB falls back exactly as before. For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI sink that advertised it. Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation") Suggested-by: Adolfo Rodrigues Assisted-by: Claude Code:claude-fable-5-1 Signed-off-by: Adrian Betschart Reviewed-by: Fangzhi Zuo Tested-by: Adolfo Rodrigues Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7) --- Documentation/admin-guide/sysctl/user.rst | 84 +++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 Documentation/admin-guide/sysctl/user.rst (limited to 'Documentation/admin-guide/sysctl/user.rst') diff --git a/Documentation/admin-guide/sysctl/user.rst b/Documentation/admin-guide/sysctl/user.rst new file mode 100644 index 000000000..c45824589 --- /dev/null +++ b/Documentation/admin-guide/sysctl/user.rst @@ -0,0 +1,84 @@ +================================= +Documentation for /proc/sys/user/ +================================= + +kernel version 4.9.0 + +Copyright (c) 2016 Eric Biederman + +------------------------------------------------------------------------------ + +This file contains the documentation for the sysctl files in +/proc/sys/user. + +The files in this directory can be used to override the default +limits on the number of namespaces and other objects that have +per user per user namespace limits. + +The primary purpose of these limits is to stop programs that +malfunction and attempt to create a ridiculous number of objects, +before the malfunction becomes a system wide problem. It is the +intention that the defaults of these limits are set high enough that +no program in normal operation should run into these limits. + +The creation of per user per user namespace objects are charged to +the user in the user namespace who created the object and +verified to be below the per user limit in that user namespace. + +The creation of objects is also charged to all of the users +who created user namespaces the creation of the object happens +in (user namespaces can be nested) and verified to be below the per user +limits in the user namespaces of those users. + +This recursive counting of created objects ensures that creating a +user namespace does not allow a user to escape their current limits. + +Currently, these files are in /proc/sys/user: + +max_cgroup_namespaces +===================== + + The maximum number of cgroup namespaces that any user in the current + user namespace may create. + +max_ipc_namespaces +================== + + The maximum number of ipc namespaces that any user in the current + user namespace may create. + +max_mnt_namespaces +================== + + The maximum number of mount namespaces that any user in the current + user namespace may create. + +max_net_namespaces +================== + + The maximum number of network namespaces that any user in the + current user namespace may create. + +max_pid_namespaces +================== + + The maximum number of pid namespaces that any user in the current + user namespace may create. + +max_time_namespaces +=================== + + The maximum number of time namespaces that any user in the current + user namespace may create. + +max_user_namespaces +=================== + + The maximum number of user namespaces that any user in the current + user namespace may create. + +max_uts_namespaces +================== + + The maximum number of user namespaces that any user in the current + user namespace may create. -- cgit v1.3.1