Re: [PATCH v3] drm/i915/bios: Use get_unaligned_* for VBT block size

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 14 Jan 2026, Kaushlendra Kumar <kaushlendra.kumar@intel.com> wrote:
> Replace pointer casts with get_unaligned_* helpers for VBT
> block size reads. This ensures endianness and alignment
> correctness in VBT parsing.
>
> Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
> v2: Fix include ordering, as per review
> v3: Update all instances in file, not just _get_blocksize
>
>  drivers/gpu/drm/i915/display/intel_bios.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 4b41068e9e35..91286fafa52b 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -27,6 +27,7 @@
>  
>  #include <linux/debugfs.h>
>  #include <linux/firmware.h>
> +#include <linux/unaligned.h>
>  
>  #include <drm/display/drm_dp_helper.h>
>  #include <drm/display/drm_dsc_helper.h>
> @@ -85,9 +86,9 @@ static u32 _get_blocksize(const u8 *block_base)
>  {
>  	/* The MIPI Sequence Block v3+ has a separate size field. */
>  	if (*block_base == BDB_MIPI_SEQUENCE && *(block_base + 3) >= 3)
> -		return *((const u32 *)(block_base + 4));
> +		return get_unaligned_le32(block_base + 4);
>  	else
> -		return *((const u16 *)(block_base + 1));
> +		return get_unaligned_le16(block_base + 1);
>  }
>  
>  /* Get BDB block size give a pointer to data after Block ID and Block Size. */
> @@ -1791,9 +1792,9 @@ find_panel_sequence_block(struct intel_display *display,
>  
>  		current_id = *(data + index);
>  		if (sequence->version >= 3)
> -			current_size = *((const u32 *)(data + index + 1));
> +			current_size = get_unaligned_le32(data + index + 1);
>  		else
> -			current_size = *((const u16 *)(data + index + 1));
> +			current_size = get_unaligned_le16(data + index + 1);
>  
>  		index += header_size;
>  
> @@ -1833,7 +1834,7 @@ static int goto_next_sequence(struct intel_display *display,
>  			if (index + 4 > total)
>  				return 0;
>  
> -			len = *((const u16 *)(data + index + 2)) + 4;
> +			len = get_unaligned_le16(data + index + 2) + 4;
>  			break;
>  		case MIPI_SEQ_ELEM_DELAY:
>  			len = 4;
> @@ -1879,7 +1880,7 @@ static int goto_next_sequence_v3(struct intel_display *display,
>  	 * includes MIPI_SEQ_ELEM_END byte, excludes the final MIPI_SEQ_END
>  	 * byte.
>  	 */
> -	size_of_sequence = *((const u32 *)(data + index));
> +	size_of_sequence = get_unaligned_le32(data + index);
>  	index += 4;
>  
>  	seq_end = index + size_of_sequence;

-- 
Jani Nikula, Intel