On Mon, Mar 28, 2022 at 05:34:27PM +0300, Jani Nikula wrote:
> Use struct detailed_timing member access instead of direct offsets to
> avoid casting.
>
> Use BUILD_BUG_ON() for sanity check.
>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 57 +++++++++++++++++++++++++-------------
> 1 file changed, 37 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 39c8bf4ca082..27a0e9bf260c 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2438,61 +2438,78 @@ drm_monitor_supports_rb(struct edid *edid)
> }
>
> static void
> -find_gtf2(struct detailed_timing *t, void *data)
> +find_gtf2(struct detailed_timing *descriptor, void *data)
> {
> - u8 *r = (u8 *)t;
> + struct detailed_timing **res = data;
>
> - if (!is_display_descriptor(t, EDID_DETAIL_MONITOR_RANGE))
> + if (!is_display_descriptor(descriptor, EDID_DETAIL_MONITOR_RANGE))
> return;
>
> - if (r[10] == 0x02)
> - *(u8 **)data = r;
> + BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.flags) != 10);
> +
> + if (descriptor->data.other_data.data.range.flags == 0x02)
> + *res = descriptor;
> }
>
> /* Secondary GTF curve kicks in above some break frequency */
> static int
> drm_gtf2_hbreak(struct edid *edid)
> {
> - u8 *r = NULL;
> + struct detailed_timing *descriptor = NULL;
> +
> + drm_for_each_detailed_block((u8 *)edid, find_gtf2, &descriptor);
>
> - drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
> - return r ? (r[12] * 2) : 0;
> + BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.formula.gtf2.hfreq_start_khz) != 12);
> +
> + return descriptor ? descriptor->data.other_data.data.range.formula.gtf2.hfreq_start_khz * 2 : 0;
> }
>
> static int
> drm_gtf2_2c(struct edid *edid)
> {
> - u8 *r = NULL;
> + struct detailed_timing *descriptor = NULL;
> +
> + drm_for_each_detailed_block((u8 *)edid, find_gtf2, &descriptor);
> +
> + BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.formula.gtf2.c) != 13);
>
> - drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
> - return r ? r[13] : 0;
> + return descriptor ? descriptor->data.other_data.data.range.formula.gtf2.c : 0;
> }
>
> static int
> drm_gtf2_m(struct edid *edid)
> {
> - u8 *r = NULL;
> + struct detailed_timing *descriptor = NULL;
>
> - drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
> - return r ? (r[15] << 8) + r[14] : 0;
> + drm_for_each_detailed_block((u8 *)edid, find_gtf2, &descriptor);
> +
> + BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.formula.gtf2.m) != 14);
> +
> + return descriptor ? le16_to_cpu(descriptor->data.other_data.data.range.formula.gtf2.m) : 0;
> }
>
> static int
> drm_gtf2_k(struct edid *edid)
> {
> - u8 *r = NULL;
> + struct detailed_timing *descriptor = NULL;
> +
> + drm_for_each_detailed_block((u8 *)edid, find_gtf2, &descriptor);
>
> - drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
> - return r ? r[16] : 0;
> + BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.formula.gtf2.k) != 16);
> +
> + return descriptor ? descriptor->data.other_data.data.range.formula.gtf2.k : 0;
> }
>
> static int
> drm_gtf2_2j(struct edid *edid)
> {
> - u8 *r = NULL;
> + struct detailed_timing *descriptor = NULL;
> +
> + drm_for_each_detailed_block((u8 *)edid, find_gtf2, &descriptor);
> +
> + BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.formula.gtf2.j) != 17);
>
> - drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
> - return r ? r[17] : 0;
> + return descriptor ? descriptor->data.other_data.data.range.formula.gtf2.j : 0;
> }
>
> /**
> --
> 2.30.2
--
Ville Syrjälä
Intel
