On Wed, Feb 21, 2024 at 06:06:24PM -0700, Karthikeyan Ramasubramanian wrote:
> Starting BDB version 239, hdr_dpcd_refresh_timeout is introduced to
> backlight BDB data. Commit 700034566d68 ("drm/i915/bios: Define more BDB
> contents") updated the backlight BDB data accordingly. This broke the
> parsing of backlight BDB data in VBT for versions 236 - 238 (both
> inclusive) and hence the backlight controls are not responding on units
> with the concerned BDB version.
>
> backlight_control information has been present in backlight BDB data
> from at least BDB version 191 onwards, if not before. Hence this patch
> extracts the backlight_control information for BDB version 191 or newer.
> Tested on Chromebooks using Jasperlake SoC (reports bdb->version = 236).
> Tested on Chromebooks using Raptorlake SoC (reports bdb->version = 251).
>
> Fixes: 700034566d68 ("drm/i915/bios: Define more BDB contents")
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Karthikeyan Ramasubramanian <kramasub@xxxxxxxxxxxx>
> ---
>
> Changes in v2:
> - removed checking the block size of the backlight BDB data
I fixed up the formatting of the commit message a bit,
added a note indicating why it's ok to remove the size
checks, and pushed to drm-intel-next. Thanks.
>
> drivers/gpu/drm/i915/display/intel_bios.c | 19 ++++---------------
> drivers/gpu/drm/i915/display/intel_vbt_defs.h | 5 -----
> 2 files changed, 4 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index aa169b0055e97..8c1eb05fe77d2 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -1042,22 +1042,11 @@ parse_lfp_backlight(struct drm_i915_private *i915,
> panel->vbt.backlight.type = INTEL_BACKLIGHT_DISPLAY_DDI;
> panel->vbt.backlight.controller = 0;
> if (i915->display.vbt.version >= 191) {
> - size_t exp_size;
> + const struct lfp_backlight_control_method *method;
>
> - if (i915->display.vbt.version >= 236)
> - exp_size = sizeof(struct bdb_lfp_backlight_data);
> - else if (i915->display.vbt.version >= 234)
> - exp_size = EXP_BDB_LFP_BL_DATA_SIZE_REV_234;
> - else
> - exp_size = EXP_BDB_LFP_BL_DATA_SIZE_REV_191;
> -
> - if (get_blocksize(backlight_data) >= exp_size) {
> - const struct lfp_backlight_control_method *method;
> -
> - method = &backlight_data->backlight_control[panel_type];
> - panel->vbt.backlight.type = method->type;
> - panel->vbt.backlight.controller = method->controller;
> - }
> + method = &backlight_data->backlight_control[panel_type];
> + panel->vbt.backlight.type = method->type;
> + panel->vbt.backlight.controller = method->controller;
> }
>
> panel->vbt.backlight.pwm_freq_hz = entry->pwm_freq_hz;
> diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> index a9f44abfc9fc2..b50cd0dcabda9 100644
> --- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> +++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> @@ -897,11 +897,6 @@ struct lfp_brightness_level {
> u16 reserved;
> } __packed;
>
> -#define EXP_BDB_LFP_BL_DATA_SIZE_REV_191 \
> - offsetof(struct bdb_lfp_backlight_data, brightness_level)
> -#define EXP_BDB_LFP_BL_DATA_SIZE_REV_234 \
> - offsetof(struct bdb_lfp_backlight_data, brightness_precision_bits)
> -
> struct bdb_lfp_backlight_data {
> u8 entry_size;
> struct lfp_backlight_data_entry data[16];
> --
> 2.44.0.rc0.258.g7320e95886-goog
--
Ville Syrjälä
Intel
