In the Linux kernel, the following vulnerability has been resolved:
drm/exynos: hdmi: report safe 640x480 mode as a fallback when no EDID found
When reading EDID fails and driver reports no modes available, the DRM core adds an artificial 1024x786 mode to the connector. Unfortunately some variants of the Exynos HDMI (like the one in Exynos4 SoCs) are not able to drive such mode, so report a safe 640x480 mode instead of nothing in case of the EDID reading failure.
This fixes the following issue observed on Trats2 board since commit 13d5b040363c ("drm/exynos: do not return negative values from .get_modes()"):
[drm] Exynos DRM: using 11c00000.fimd device for DMA mapping operations exynos-drm exynos-drm: bound 11c00000.fimd (ops fimd_component_ops) exynos-drm exynos-drm: bound 12c10000.mixer (ops mixer_component_ops) exynos-dsi 11c80000.dsi: [drm:samsung_dsim_host_attach] Attached s6e8aa0 device (lanes:4 bpp:24 mode-flags:0x10b) exynos-drm exynos-drm: bound 11c80000.dsi (ops exynos_dsi_component_ops) exynos-drm exynos-drm: bound 12d00000.hdmi (ops hdmi_component_ops) [drm] Initialized exynos 1.1.0 20180330 for exynos-drm on minor 1 exynos-hdmi 12d00000.hdmi: [drm:hdmiphy_enable.part.0] ERROR PLL could not reach steady state panel-samsung-s6e8aa0 11c80000.dsi.0: ID: 0xa2, 0x20, 0x8c exynos-mixer 12c10000.mixer: timeout waiting for VSYNC ------------[ cut here ]------------ WARNING: CPU: 1 PID: 11 at drivers/gpu/drm/drm_atomic_helper.c:1682 drm_atomic_helper_wait_for_vblanks.part.0+0x2b0/0x2b8 [CRTC:70:crtc-1] vblank wait timed out Modules linked in: CPU: 1 PID: 11 Comm: kworker/u16:0 Not tainted 6.9.0-rc5-next-20240424 #14913 Hardware name: Samsung Exynos (Flattened Device Tree) Workqueue: events_unbound deferred_probe_work_func Call trace: unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x68/0x88 dump_stack_lvl from __warn+0x7c/0x1c4 __warn from warn_slowpath_fmt+0x11c/0x1a8 warn_slowpath_fmt from...