Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933443AbaFLNSA (ORCPT ); Thu, 12 Jun 2014 09:18:00 -0400 Received: from purkki.adurom.net ([80.68.90.206]:43460 "EHLO purkki.adurom.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932554AbaFLNR4 (ORCPT ); Thu, 12 Jun 2014 09:17:56 -0400 X-Greylist: delayed 2099 seconds by postgrey-1.27 at vger.kernel.org; Thu, 12 Jun 2014 09:17:56 EDT From: Kalle Valo To: Aaron Lu Cc: linux-kernel@vger.kernel.org Subject: video: X sets brightness to zero after resume Date: Thu, 12 Jun 2014 15:42:55 +0300 Message-ID: <871tuu1epc.fsf@purkki.adurom.net> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Aaron, after your commit 0e9f81d3b7c ("ACPI / video: Add systems that should favour native backlight interface") I have had an regression that every time after resume the display brightness has been set to zero and I need to manually set it to non-zero to see something again. Finally I started to investigate this more closely and it seems that X sets it to zero for some reason. I added a WARN_ON() and few printks to brightness_store() in drivers/video/backlight/backlight.c and this is what I see during resume: [ 49.228221] ------------[ cut here ]------------ [ 49.228229] WARNING: CPU: 1 PID: 1133 at drivers/video/backlight/backlight.c:173 brightness_store+0x3c/0x120( ) [ 49.228230] Modules linked in: ctr ccm uvcvideo videobuf2_core videodev videobuf2_vmalloc videobuf2_memops fu se arc4 iwldvm sha256_generic kvm_intel kvm mac80211 snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_gene ric iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 snd_hda_intel snd_hda_controller nf_nat_ipv4 nf_nat snd_hda_cod ec nf_conntrack snd_hwdep snd_pcm_oss iwlwifi snd_mixer_oss snd_pcm ip_tables x_tables thinkpad_acpi snd_seq_dum my snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq cfg80211 snd_timer snd_seq_device snd bnep rfcomm bluetooth psmouse soundcore nvram ehci_pci ehci_hcd rfkill wmi binfmt_misc ext4 jbd2 mbcache sd_mod fbcon tileblit font bitblit softcursor i915 drm_kms_helper drm cfbcopyarea i2c_algo_bit intel_gtt agpgart i2c_core video xhci_hcd cfbimgblt cfbfillrect e1000e sdhci_pci sdhci ptp pps_core mmc_core ahci libahci [ 49.228281] CPU: 1 PID: 1133 Comm: Xorg Tainted: G W 3.15.0-rc7-wl-ath+ #259 [ 49.228282] Hardware name: LENOVO 2324JB2/2324JB2, BIOS G2ET82WW (2.02 ) 09/11/2012 [ 49.228283] 0000000000000000 ffffffff817e4000 ffffffff814cbee3 0000000000000000 [ 49.228285] ffffffff810493bc ffff88020e2d1c98 ffff880213bc9f10 0000000000000002 [ 49.228287] ffff8800c5dfc198 ffff88020d7cbf50 ffffffff81290a1c ffff88020e792800 [ 49.228288] Call Trace: [ 49.228293] [] ? dump_stack+0x41/0x51 [ 49.228296] [] ? warn_slowpath_common+0x8c/0xc0 [ 49.228298] [] ? brightness_store+0x3c/0x120 [ 49.228301] [] ? kernfs_fop_write+0x112/0x170 [ 49.228304] [] ? vfs_write+0xcb/0x1f0 [ 49.228306] [] ? SyS_write+0x50/0xb0 [ 49.228308] [] ? system_call_fastpath+0x16/0x1b [ 49.228309] ---[ end trace a1f60d12df64bdbe ]--- [ 49.228310] brightness=0 [ 49.228310] set brightness to 0 And this is PID 1133: root 1133 0.7 0.2 131504 20192 tty7 Ss+ 15:16 0:00 /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch -background none If I set video.use_native_backlight=0 in kernel command line the problem goes away. Or if I revert your commit 0e9f81d3b7c the problem also goes away. Any ideas? My setup is: Thinkpad X230 Ubuntu 12.04 64-bit i3 window manager xserver-xorg 1:7.6+12ubuntu2 -- Kalle Valo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/