Attachment 894577 Details for Bug 1093171 – PATCH: nouveau: Don't check acpi_video_backlight_support() before registering backlight

[patch] PATCH: nouveau: Don't check acpi_video_backlight_support() before registering backlight

0001-nouveau-Don-t-check-acpi_video_backlight_support-bef.patch (text/plain), 2.57 KB, created by Hans de Goede on 2014-05-12 07:25:56 UTC

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Creator: Hans de Goede

Created: 2014-05-12 07:25:56 UTC

Size: 2.57 KB

patch

obsolete

>From 06afd82e632609b8ca0c2155b3ad3a4d259c58df Mon Sep 17 00:00:00 2001
>From: Hans de Goede <hdegoede@redhat.com>
>Date: Mon, 12 May 2014 08:54:13 +0200
>Subject: [PATCH v2] nouveau: Don't check acpi_video_backlight_support() before
> registering backlight
>
>acpi_video_backlight_support() is supposed to be called by other (vendor
>specific) firmware backlight controls, not by native / raw backlight controls
>like nv_backlight.
>
>Userspace will normally prefer firmware interfaces over raw interfaces, so
>if acpi_video backlight support is present it will use that even if
>nv_backlight is registered as well.
>
>Except when video.use_native_backlight is present on the kernel cmdline
>(or enabled through a dmi based quirk). As the name indicates the goal here
>is to make only the raw interface available to userspace so that it will use
>that (it only does this when it sees a win8 compliant bios).
>
>This is done by:
>1) Not registering any acpi_video# backlight devices; and
>2) Making acpi_video_backlight_support() return true so that other firmware
>drivers, ie acer_wmi, thinkpad_acpi, dell_laptop, etc. Don't register their
>own vender specific interfaces.
>
>Currently nouveau breaks this setup, as when acpi_video_backlight_support()
>returns true, it does not register itself, resulting in no backlight control
>at all.
>
>This is esp. going to be a problem with 3.16 which will default to
>video.use_native_backlight=1, and thus nouveau based laptops with a win8 bios
>will get no backlight control at all.
>
>Also see: https://bugzilla.redhat.com/show_bug.cgi?id=1093171
>
>Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>---
> drivers/gpu/drm/nouveau/nouveau_backlight.c | 9 ---------
> 1 file changed, 9 deletions(-)
>
>diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c
>index 630f6e8..2c1e4aa 100644
>--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
>+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
>@@ -31,7 +31,6 @@
>  */
> 
> #include <linux/backlight.h>
>-#include <linux/acpi.h>
> 
> #include "nouveau_drm.h"
> #include "nouveau_reg.h"
>@@ -222,14 +221,6 @@ nouveau_backlight_init(struct drm_device *dev)
> 	struct nouveau_device *device = nv_device(drm->device);
> 	struct drm_connector *connector;
> 
>-#ifdef CONFIG_ACPI
>-	if (acpi_video_backlight_support()) {
>-		NV_INFO(drm, "ACPI backlight interface available, "
>-			     "not registering our own\n");
>-		return 0;
>-	}
>-#endif
>-
> 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
> 		if (connector->connector_type != DRM_MODE_CONNECTOR_LVDS &&
> 		    connector->connector_type != DRM_MODE_CONNECTOR_eDP)
>-- 
>1.9.0
>

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Attachments on bug 1093171: 894577