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intel_extreme: adjust brightness level for Gen4

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preserve bits before Gen4

Change-Id: Icf80ec469c3682223f0db1744a5c923fb06bd7fd
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5190
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
This commit is contained in:
Jérôme Duval 2022-04-09 09:49:53 +02:00 committed by Adrien Destugues
parent d271377590
commit e5d9d907ee
1 changed files with 20 additions and 6 deletions
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20
src/add-ons/accelerants/intel_extreme/mode.cpp
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@ -632,15 +632,24 @@ intel_set_brightness(float brightness)
write32(intel_get_backlight_register(false), duty | (period << 16));
} else {
// On older devices there is a single register with both period and duty cycle
uint32_t period = read32(intel_get_backlight_register(true)) >> 16;
uint32 tmp = read32(intel_get_backlight_register(true));
uint32_t period = tmp >> 16;
uint32_t mask = 0xffff;
uint32_t shift = 0;
if (gInfo->shared_info->device_type.Generation() < 4) {
// The low bit must be masked out because
// it is apparently used for something else on some Atom machines (no
// reference to that in the documentation that I know of).
uint32_t duty = (uint32_t)(period * brightness) & 0xfffe;
mask = 0xfffe;
shift = 1;
period = tmp >> 17;
}
uint32_t duty = (uint32_t)(period * brightness);
duty = std::max(duty, (uint32_t)gInfo->shared_info->min_brightness);
duty <<= shift;
write32(intel_get_backlight_register(false), duty | (period << 16));
write32(intel_get_backlight_register(false), (duty & mask) | (tmp & ~mask));
}
return B_OK;
@ -664,6 +673,11 @@ intel_get_brightness(float* brightness)
} else {
period = read32(intel_get_backlight_register(true)) >> 16;
duty = read32(intel_get_backlight_register(false)) & 0xffff;
if (gInfo->shared_info->device_type.Generation() < 4) {
period >>= 1;
duty >>= 1;
}
}
*brightness = (float)duty / period;