From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- Documentation/admin-guide/edid.rst | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 Documentation/admin-guide/edid.rst (limited to 'Documentation/admin-guide/edid.rst') diff --git a/Documentation/admin-guide/edid.rst b/Documentation/admin-guide/edid.rst new file mode 100644 index 000000000..1a9b965aa --- /dev/null +++ b/Documentation/admin-guide/edid.rst @@ -0,0 +1,27 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +EDID +==== + +In the good old days when graphics parameters were configured explicitly +in a file called xorg.conf, even broken hardware could be managed. + +Today, with the advent of Kernel Mode Setting, a graphics board is +either correctly working because all components follow the standards - +or the computer is unusable, because the screen remains dark after +booting or it displays the wrong area. Cases when this happens are: + +- The graphics board does not recognize the monitor. +- The graphics board is unable to detect any EDID data. +- The graphics board incorrectly forwards EDID data to the driver. +- The monitor sends no or bogus EDID data. +- A KVM sends its own EDID data instead of querying the connected monitor. + +Adding the kernel parameter "nomodeset" helps in most cases, but causes +restrictions later on. + +As a remedy for such situations, the kernel configuration item +CONFIG_DRM_LOAD_EDID_FIRMWARE was introduced. It allows to provide an +individually prepared or corrected EDID data set in the /lib/firmware +directory from where it is loaded via the firmware interface. -- cgit v1.3.1