61 lines
2.6 KiB
Diff
61 lines
2.6 KiB
Diff
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From 4cd2b2cf8ca585d15ebc859701b346658262b5bb Mon Sep 17 00:00:00 2001
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From: Denis Tikhomirov <dvtikhomirov@gmail.com>
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Date: Thu, 5 Jun 2014 23:59:40 +0400
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Subject: [PATCH] backlight: Do not clamp brightness for LEDs
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https://bugs.freedesktop.org/show_bug.cgi?id=77092
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On Thu, Jun 05, 2014 at 08:37:20AM +0200, Lennart Poettering wrote:
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> The patch is line-broken, please send an uncorrupted patch!
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I am very sorry, I forgot that my client limits line width. I will use
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mutt now on.
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> clamp_brightness() clamps the brightness value to the range of the
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> actual device. This is a recent addition that was added to deal with
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> driver updates where the resolution is changed. I don't think this part
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> should be dropped for LED devices. The clamp_brightness() call hence
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> should be called unconditionally, however, internally it should use a
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> different min_brightness value if something is an !backlight devices...
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Thank you for explanation, this sounds very reasonable to me. Please,
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see updated patch:
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---
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src/backlight/backlight.c | 13 ++++++++++---
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1 file changed, 10 insertions(+), 3 deletions(-)
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diff --git src/backlight/backlight.c src/backlight/backlight.c
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index 691472c..4d94ebf 100644
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--- src/backlight/backlight.c
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+++ src/backlight/backlight.c
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@@ -225,11 +225,13 @@ static unsigned get_max_brightness(struct udev_device *device) {
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/* Some systems turn the backlight all the way off at the lowest levels.
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* clamp_brightness clamps the saved brightness to at least 1 or 5% of
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- * max_brightness. This avoids preserving an unreadably dim screen, which
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- * would otherwise force the user to disable state restoration. */
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+ * max_brightness in case of 'backlight' subsystem. This avoids preserving
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+ * an unreadably dim screen, which would otherwise force the user to
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+ * disable state restoration. */
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static void clamp_brightness(struct udev_device *device, char **value, unsigned max_brightness) {
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int r;
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unsigned brightness, new_brightness, min_brightness;
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+ const char *subsystem;
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r = safe_atou(*value, &brightness);
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if (r < 0) {
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@@ -237,7 +239,12 @@ static void clamp_brightness(struct udev_device *device, char **value, unsigned
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return;
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}
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- min_brightness = MAX(1U, max_brightness/20);
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+ subsystem = udev_device_get_subsystem(device);
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+ if (streq_ptr(subsystem, "backlight"))
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+ min_brightness = MAX(1U, max_brightness/20);
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+ else
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+ min_brightness = 0;
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+
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new_brightness = CLAMP(brightness, min_brightness, max_brightness);
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if (new_brightness != brightness) {
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char *old_value = *value;
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--
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1.7.9.2
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