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drm/i915/bdb: Fix version check

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With patch "drm/i915/vbt: Fix backlight parsing for VBT 234+"
the size of bdb_lfp_backlight_data structure has been increased,
causing if-statement in the parse_lfp_backlight function
that comapres this structure size to the one retrieved from BDB,
always to fail for older revisions.
This patch calculates expected size of the structure for a given
BDB version and compares it with the value gathered from BDB.
Tested on Chromebook Pixelbook (Nocturne) (reports bdb->version = 221)

Fixes: d381baad29 ("drm/i915/vbt: Fix backlight parsing for VBT 234+")

Tested-by: Lukasz Majczak <lma@semihalf.com>
Signed-off-by: Lukasz Majczak <lma@semihalf.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930134606.227234-1-lma@semihalf.com
(cherry picked from commit 4378daf5d0)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Lukasz Majczak 2021-09-30 15:46:06 +02:00 committed by Jani Nikula
parent a532cde31d
commit fdddf8c3a4
2 changed files with 21 additions and 6 deletions
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22
drivers/gpu/drm/i915/display/intel_bios.c
View File

@ -451,13 +451,23 @@ parse_lfp_backlight(struct drm_i915_private *i915,
}
i915->vbt.backlight.type = INTEL_BACKLIGHT_DISPLAY_DDI;
if (bdb->version >= 191 &&
get_blocksize(backlight_data) >= sizeof(*backlight_data)) {
const struct lfp_backlight_control_method *method;
if (bdb->version >= 191) {
size_t exp_size;
method = &backlight_data->backlight_control[panel_type];
i915->vbt.backlight.type = method->type;
i915->vbt.backlight.controller = method->controller;
if (bdb->version >= 236)
exp_size = sizeof(struct bdb_lfp_backlight_data);
else if (bdb->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];
i915->vbt.backlight.type = method->type;
i915->vbt.backlight.controller = method->controller;
}
}
i915->vbt.backlight.pwm_freq_hz = entry->pwm_freq_hz;

5
drivers/gpu/drm/i915/display/intel_vbt_defs.h
View File

@ -814,6 +814,11 @@ 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];