[PATCH 5.14 085/151] drm/i915/bdb: Fix version check
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-10-11 14:07:49
Also in:
lkml
Subsystem:
drm drivers, intel drm display for xe and i915 drivers, intel drm i915 driver (meteor lake, dg2 and older excluding poulsbo, moorestown and derivative), the rest · Maintainers:
David Airlie, Simona Vetter, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen, Tvrtko Ursulin, Linus Torvalds
From: Lukasz Majczak <redacted>
[ Upstream commit fdddf8c3a477f77b3a623f220e78d45e89fc50d5 ]
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: d381baad29b4 ("drm/i915/vbt: Fix backlight parsing for VBT 234+")
Tested-by: Lukasz Majczak <redacted>
Signed-off-by: Lukasz Majczak <redacted>
Reviewed-by: José Roberto de Souza <redacted>
Signed-off-by: José Roberto de Souza <redacted>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930134606.227234-1-lma@semihalf.com
(cherry picked from commit 4378daf5d04eed59724e6d0e74755e17dce2e105)
Signed-off-by: Jani Nikula <redacted>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/i915/display/intel_bios.c | 22 ++++++++++++++-----
drivers/gpu/drm/i915/display/intel_vbt_defs.h | 5 +++++
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index aa667fa71158..106f696e50a0 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c@@ -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;
diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
index dbe24d7e7375..cf1ffe4a0e46 100644
--- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h@@ -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];
--
2.33.0