kernel/linux.git/drivers/gpu/drm/amd/display/dc/bios, branch v7.1

drm/amd/display: Bound VBIOS record-chain walk loops

2026-06-03T18:45:44+00:00

[Why & How] All record-chain walk loops in bios_parser.c and bios_parser2.c use for(;;) and only terminate on a 0xFF record_type sentinel or zero record_size. A malformed VBIOS image missing the terminator record causes unbounded iteration at probe time, potentially hundreds of thousands of iterations with record_size=1. In the final iterations near the BIOS image boundary, struct casts beyond the 2-byte header validated by GET_IMAGE can also read out of bounds. Cap all 14 record-chain walk loops to BIOS_MAX_NUM_RECORD (256) iterations. The atombios.h defines up to 22 distinct record types and atomfirmware.h has 13. Assuming an average of less than 10 records per type (which is reasonable since most are connector- based) 256 is a generous upper bound. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Assisted-by: Copilot:claude-opus-4.6 Mythos Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 95700a3d660287ed657d6892f7be9ffc0e294a93) Cc: stable@vger.kernel.org

drm/amd/display: Reject gpio_bitshift >= 32 in bios_parser_get_gpio_pin_info()

2026-06-03T18:45:02+00:00

[Why & How] gpio_bitshift is a uint8_t read directly from the VBIOS GPIO pin table. If the value is >= 32, the expression "1 << gpio_bitshift" triggers undefined behaviour in C (shift count exceeds type width). On x86 the shift is silently masked to 5 bits, producing an incorrect GPIO mask that may cause wrong MMIO register bits to be toggled. Validate gpio_bitshift before use and return BP_RESULT_BADBIOSTABLE for out-of-range values. Fixes: ae79c310b1a6 ("drm/amd/display: Add DCE12 bios parser support") Assisted-by: Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit eadf438ab8d370b9d19acee9359918c85afeb80d) Cc: stable@vger.kernel.org

drm/amd/display: Clamp VBIOS HDMI retimer register count to array size

2026-06-03T18:43:49+00:00

[Why & How] The VBIOS integrated info tables (v1_11 and v2_1) contain HdmiRegNum and Hdmi6GRegNum fields that are used as loop bounds when copying retimer I2C register settings into fixed-size arrays (dp*_ext_hdmi_reg_settings[9] and dp*_ext_hdmi_6g_reg_settings[3]). These u8 fields are not validated before use, so a malformed VBIOS can specify values up to 255, causing an out-of-bounds heap write during driver probe. Clamp each register count to the destination array size using min_t() before the copy loops, in both get_integrated_info_v11() and get_integrated_info_v2_1(). Assisted-by: GitHub Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 5a7f0ef90195940c54b0f5bb85b87da55f038c69) Cc: stable@vger.kernel.org

drm/amd/display: Validate GPIO pin LUT table size before iterating

2026-05-19T16:13:29+00:00

[Why&How] The GPIO pin table parsers in get_gpio_i2c_info() and bios_parser_get_gpio_pin_info() derive an element count from the VBIOS table_header.structuresize field, then iterate over gpio_pin[] entries. However, GET_IMAGE() only validates that the table header itself fits within the BIOS image. If the VBIOS reports a structuresize larger than the actual mapped data, the loop reads past the end of the BIOS image, causing an out-of-bounds read. Fix this by calling bios_get_image() to validate that the full claimed structuresize is accessible within the BIOS image before entering the loop in both functions. Assisted-by: GitHub Copilot:claude-opus-4-6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit ba5e95b43b773ae1bf1f66ee6b31eb774e65afe3) Cc: stable@vger.kernel.org

drm/amd/display: Fix integer overflow in bios_get_image()

2026-05-19T16:13:07+00:00

[Why&How] The bounds check in bios_get_image() computes 'offset + size' using unsigned 32-bit arithmetic before comparing against bios_size. If a VBIOS image contains a near-UINT32_MAX offset the addition wraps to a small value, the comparison passes, and the function returns a wild pointer past the VBIOS mapping. Additionally, the comparison uses '<' (strict), which incorrectly rejects the valid exact-fit case where offset + size == bios_size. Fix both issues by restructuring the check to avoid the addition entirely: first reject if offset alone exceeds bios_size, then check size against the remaining space (bios_size - offset). This eliminates the overflow and correctly permits exact-fit accesses. Assisted-by: GitHub Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit d40fb392af659c4a02b560319f226842f6ec1a95) Cc: stable@vger.kernel.org

drm/amd/display: Read EDID from VBIOS embedded panel info

2026-04-29T14:41:40+00:00

Some board manufacturers hardcode the EDID for the embedded panel in the VBIOS. This EDID should be used when the panel doesn't have a DDC. For reference, see the legacy non-DC display code: amdgpu_atombios_encoder_get_lcd_info() This is necessary to support embedded connectors without DDC. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Link: https://gitlab.freedesktop.org/drm/amd/-/work_items/5192 Signed-off-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit eb105e63b474c11ef6a84a1c6b18100d851ff364)

drm/amd/display: Restore analog connector support

2026-04-24T15:08:15+00:00

[Why] The analog connector support was accidentally removed, causing a crash when connecting an analog monitor. [How] This patch restores the functions and pointers required for proper analog and DP bridge encoder support on legacy GPUs. V2: Restore the external encoder control functions. V3: - Restore BIOS parser external encoder DAC load detection - Restore stream initialization and source selection changes Fixes: e56e3cff2a1b ("drm/amd/display: Sync dcn42 with DC 3.2.373") Cc: Timur Kristóf Signed-off-by: Roman Li Reviewed-by: Alex Hung Reviewed-by: Timur Kristóf Tested-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit cea8349e4494d2892ea57eef3fe4a8987464a876)

drm/amd/display: Fixed Silence complier warnings in dc

2026-03-30T19:12:15+00:00

[Why] Resolve compiler warnings by marking unused parameters explicitly. [How] In .c and .h function definitions, keep parameter names in signatures and add a line with `(void)param;` in function body Preserved function signatures and avoids breaking code paths that may reference the parameter under conditional compilation. Reviewed-by: Dillon Varone Reviewed-by: Austin Zheng Signed-off-by: Gaghik Khachatrian Signed-off-by: Chuanyu Tseng Signed-off-by: Alex Deucher

drm/amd/display: bios_parser: fix GPIO I2C line off-by-one

2026-03-30T18:39:18+00:00

get_gpio_i2c_info() computes the number of GPIO I2C assignment records present in the BIOS table and then uses bfI2C_LineMux as an array index into header->asGPIO_Info[]. The current check only rejects values strictly larger than the record count, so an index equal to count still falls through and reaches the fixed table one element past the end. Reject indices at or above the number of available records before using them as an array index. Signed-off-by: Pengpeng Hou Signed-off-by: Alex Deucher

drm/amd/display: Sync dcn42 with DC 3.2.373

2026-03-11T17:58:07+00:00

This patch provides a bulk merge to align driver support for DCN42 with Display Core version 3.2.373. It includes upgrade for: - clk_mgr - dml2/dml21 - optc - hubp - mpc - optc - hwseq Acked-by: Aurabindo Pillai Signed-off-by: Roman Li Signed-off-by: Alex Hung Tested-by: Dan Wheeler Signed-off-by: Alex Deucher