kernel/linux.git/drivers/gpu/drm/amd/display/dc/bios, branch v6.6.150

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

2026-07-04T11:42:18+00:00

[ Upstream commit ff287df16a1a58aca78b08d1f3ee09fc44da0351 ] [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 Signed-off-by: Sasha Levin

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

2026-06-19T11:39:37+00:00

commit fb0707ce00eef4e2d60c3020e1c0432739703e4a upstream. [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 Signed-off-by: Greg Kroah-Hartman

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

2026-06-19T11:39:33+00:00

commit 49c3da65961fe9857c831d47fa1989084e87514a upstream. [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 Signed-off-by: Greg Kroah-Hartman

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

2026-06-01T15:43:09+00:00

commit 86d2b20644b11d21fe52c596e6e922b4590a3e3f upstream. [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 Signed-off-by: Greg Kroah-Hartman

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

2026-06-01T15:43:09+00:00

commit cd86529ec61474a38c3837fb7823790a7c3f8cce upstream. [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 Signed-off-by: Greg Kroah-Hartman

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

2026-05-23T11:03:30+00:00

[ Upstream commit 9ea16f64189bf7b6ba50fc7f0325b3c1f836d105 ] 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) Signed-off-by: Sasha Levin

drm/amd/display: Fix logical vs bitwise bug in get_embedded_panel_info_v2_1()

2026-01-11T14:21:31+00:00

[ Upstream commit 1a79482699b4d1e43948d14f0c7193dc1dcad858 ] The .H_SYNC_POLARITY and .V_SYNC_POLARITY variables are 1 bit bitfields of a u32. The ATOM_HSYNC_POLARITY define is 0x2 and the ATOM_VSYNC_POLARITY is 0x4. When we do a bitwise negate of 0, 2, or 4 then the last bit is always 1 so this code always sets .H_SYNC_POLARITY and .V_SYNC_POLARITY to true. This code is instead intended to check if the ATOM_HSYNC_POLARITY or ATOM_VSYNC_POLARITY flags are set and reverse the result. In other words, it's supposed to be a logical negate instead of a bitwise negate. Fixes: ae79c310b1a6 ("drm/amd/display: Add DCE12 bios parser support") Signed-off-by: Dan Carpenter Reviewed-by: Alex Hung Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Fix fractional fb divider in set_pixel_clock_v3

2025-08-28T14:28:43+00:00

commit 10507478468f165ea681605d133991ed05cdff62 upstream. For later VBIOS versions, the fractional feedback divider is calculated as the remainder of dividing the feedback divider by a factor, which is set to 1000000. For reference, see: - calculate_fb_and_fractional_fb_divider - calc_pll_max_vco_construct However, in case of old VBIOS versions that have set_pixel_clock_v3, they only have 1 byte available for the fractional feedback divider, and it's expected to be set to the remainder from dividing the feedback divider by 10. For reference see the legacy display code: - amdgpu_pll_compute - amdgpu_atombios_crtc_program_pll This commit fixes set_pixel_clock_v3 by dividing the fractional feedback divider passed to the function by 100000. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Signed-off-by: Timur Kristóf Acked-by: Alex Deucher Reviewed-by: Rodrigo Siqueira Reviewed-by: Alex Hung Signed-off-by: Alex Deucher (cherry picked from commit 027e7acc7e17802ebf28e1edb88a404836ad50d6) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Check BIOS images before it is used

2024-09-08T05:54:48+00:00

[ Upstream commit 8b0ddf19cca2a352b2a7e01d99d3ba949a99c84c ] BIOS images may fail to load and null checks are added before they are used. This fixes 6 NULL_RETURNS issues reported by Coverity. Reviewed-by: Harry Wentland Acked-by: Hamza Mahfooz Signed-off-by: Alex Hung Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Fix Coverity INTERGER_OVERFLOW within construct_integrated_info

2024-09-08T05:54:38+00:00

[ Upstream commit 176abbcc71952e23009a6ed194fd203b99646884 ] [Why] For substrcation, coverity reports integer overflow warning message when variable type is uint32_t. [How] Change varaible type to int32_t. Reviewed-by: Alex Hung Reviewed-by: Harry Wentland Acked-by: Tom Chung Signed-off-by: Hersen Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin