Advanced apologies if this is the wrong place to raise this issue. I hope this report adequately illustrates the problem. I installed a gentoo system on my new laptop, on first boot the screen is blank : the backlight is off. I can make out text with a flashlight. If I log on as root I can switch the backlight on with the command "setpci -s 00:02.0 F4.B=00" (got this tip from the net). Brightness control does not work. I compiled kernel with i915 driver (I think : ->Device Drivers ->Graphics support ->Direct Rendering Manager -> Intel 8xx/9xx/G3x/G4x/HD Graphics), with "Enable modesetting on intel by default" activated. I can get a display by appending "nomodeset" to the Grub boot command, I believe this precludes the use of intel drivers for X, it does not permit adequate screen resolution for terminal. Same results if I deactivate "Enable modesetting on intel by default". I tried kernel 3.0.3 : same issue. I tried Ubuntu 11.04 and mint 11 : same issue. Debian-Mint works, didn't investigate why, but suppose older kernel version : from forum posts I understand this issue appeared with recent kernels, someone specifies 2.6.38.8 as first introducing the bug. Googleing this issue makes me suspect that all 4500M users are concerned, and would be affected when they upgrade to newer kernels. Forum thread where I discuss this issue (I provide more system info there [lspci, kernel config, gentoo configuration]) : http://forums.gentoo.org/viewtopic-p-6797468.html#6797468 Nice bug report for ubuntu, several people and machines affected : https://bugs.launchpad.net/ubuntu/+source/linux/+bug/752165 Kernel bug report (I'm wondering if this guy reported the issue in the wrong place) : https://bugzilla.kernel.org/show_bug.cgi?id=35072#c1 I will be happy to provide any help/further information that I can, I am on holiday at the moment, I have web access only once a week, but I will respond as soon as possible. Thank you. System information : Acer Aspire 5736Z Mobile Intel® GM45 Express chipset Gentoo linux uname -r : 2.6.39-gentoo-r3 uname -m : x86_64 xf86-video-intel-2.14.0 xorg-server-1.10.2 libdrm-2.4.26 mesa-7.10.3 xorg.conf : default (none) glxinfo : see end of post glxinfo : name of display: :0.0 display: :0 screen: 0 direct rendering: Yes server glx vendor string: SGI server glx version string: 1.4 server glx extensions: GLX_ARB_multisample, GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer, GLX_OML_swap_method, GLX_SGI_make_current_read, GLX_SGI_swap_control, GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, GLX_INTEL_swap_event client glx vendor string: Mesa Project and SGI client glx version string: 1.4 client glx extensions: GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context, GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer, GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control, GLX_SGI_make_current_read, GLX_SGI_swap_control, GLX_SGI_video_sync, GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, GLX_EXT_texture_from_pixmap, GLX_INTEL_swap_event GLX version: 1.4 GLX extensions: GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context, GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer, GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control, GLX_SGI_make_current_read, GLX_SGI_swap_control, GLX_SGI_video_sync, GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, GLX_EXT_texture_from_pixmap, GLX_INTEL_swap_event OpenGL vendor string: Tungsten Graphics, Inc OpenGL renderer string: Mesa DRI Mobile Intel�� GM45 Express Chipset OpenGL version string: 2.1 Mesa 7.10.3 OpenGL shading language version string: 1.20 OpenGL extensions: GL_ARB_copy_buffer, GL_ARB_depth_clamp, GL_ARB_depth_texture, GL_ARB_draw_buffers, GL_ARB_draw_elements_base_vertex, GL_ARB_explicit_attrib_location, GL_ARB_fragment_coord_conventions, GL_ARB_fragment_program, GL_ARB_fragment_program_shadow, GL_ARB_fragment_shader, GL_ARB_framebuffer_object, GL_ARB_half_float_pixel, GL_ARB_half_float_vertex, GL_ARB_map_buffer_range, GL_ARB_multisample, GL_ARB_multitexture, GL_ARB_occlusion_query, GL_ARB_pixel_buffer_object, GL_ARB_point_parameters, GL_ARB_point_sprite, GL_ARB_provoking_vertex, GL_ARB_seamless_cube_map, GL_ARB_shader_objects, GL_ARB_shading_language_100, GL_ARB_shadow, GL_ARB_sync, GL_ARB_texture_border_clamp, GL_ARB_texture_compression, GL_ARB_texture_cube_map, GL_ARB_texture_env_add, GL_ARB_texture_env_combine, GL_ARB_texture_env_crossbar, GL_ARB_texture_env_dot3, GL_ARB_texture_mirrored_repeat, GL_ARB_texture_non_power_of_two, GL_ARB_texture_rectangle, GL_ARB_texture_rg, GL_ARB_texture_swizzle, GL_ARB_transpose_matrix, GL_ARB_vertex_array_bgra, GL_ARB_vertex_array_object, GL_ARB_vertex_buffer_object, GL_ARB_vertex_program, GL_ARB_vertex_shader, GL_ARB_window_pos, GL_EXT_abgr, GL_EXT_bgra, GL_EXT_blend_color, GL_EXT_blend_equation_separate, GL_EXT_blend_func_separate, GL_EXT_blend_logic_op, GL_EXT_blend_minmax, GL_EXT_blend_subtract, GL_EXT_compiled_vertex_array, GL_EXT_copy_texture, GL_EXT_draw_buffers2, GL_EXT_draw_range_elements, GL_EXT_fog_coord, GL_EXT_framebuffer_blit, GL_EXT_framebuffer_multisample, GL_EXT_framebuffer_object, GL_EXT_gpu_program_parameters, GL_EXT_multi_draw_arrays, GL_EXT_packed_depth_stencil, GL_EXT_packed_pixels, GL_EXT_pixel_buffer_object, GL_EXT_point_parameters, GL_EXT_polygon_offset, GL_EXT_provoking_vertex, GL_EXT_rescale_normal, GL_EXT_secondary_color, GL_EXT_separate_shader_objects, GL_EXT_separate_specular_color, GL_EXT_shadow_funcs, GL_EXT_stencil_two_side, GL_EXT_stencil_wrap, GL_EXT_subtexture, GL_EXT_texture3D, GL_EXT_texture_cube_map, GL_EXT_texture_edge_clamp, GL_EXT_texture_env_add, GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3, GL_EXT_texture_filter_anisotropic, GL_EXT_texture_lod_bias, GL_EXT_texture_object, GL_EXT_texture, GL_EXT_texture_rectangle, GL_EXT_texture_sRGB, GL_EXT_texture_swizzle, GL_EXT_vertex_array_bgra, GL_EXT_vertex_array, GL_OES_EGL_image, GL_OES_read_format, GL_3DFX_texture_compression_FXT1, GL_APPLE_client_storage, GL_APPLE_object_purgeable, GL_APPLE_packed_pixels, GL_APPLE_vertex_array_object, GL_ATI_blend_equation_separate, GL_ATI_envmap_bumpmap, GL_ATI_separate_stencil, GL_ATI_texture_env_combine3, GL_IBM_multimode_draw_arrays, GL_IBM_rasterpos_clip, GL_IBM_texture_mirrored_repeat, GL_INGR_blend_func_separate, GL_MESA_pack_invert, GL_MESA_texture_signed_rgba, GL_MESA_window_pos, GL_MESA_ycbcr_texture, GL_NV_blend_square, GL_NV_depth_clamp, GL_NV_light_max_exponent, GL_NV_packed_depth_stencil, GL_NV_texgen_reflection, GL_NV_texture_env_combine4, GL_NV_texture_rectangle, GL_NV_vertex_program1_1, GL_NV_vertex_program, GL_SGIS_generate_mipmap, GL_SGIS_texture_border_clamp, GL_SGIS_texture_edge_clamp, GL_SGIS_texture_lod, GL_SUN_multi_draw_arrays 32 GLX Visuals visual x bf lv rg d st colorbuffer sr ax dp st accumbuffer ms cav id dep cl sp sz l ci b ro r g b a F gb bf th cl r g b a ns b eat ---------------------------------------------------------------------------- 0x021 24 tc 0 32 0 r y . 8 8 8 8 . . 0 24 8 0 0 0 0 0 0 None 0x022 24 dc 0 32 0 r y . 8 8 8 8 . . 0 24 8 0 0 0 0 0 0 None 0x08f 24 tc 0 24 0 r . . 8 8 8 0 . . 0 0 0 0 0 0 0 0 0 None 0x090 24 tc 0 24 0 r y . 8 8 8 0 . . 0 0 0 0 0 0 0 0 0 None 0x091 24 tc 0 24 0 r y . 8 8 8 0 . . 0 0 0 0 0 0 0 0 0 None 0x092 24 tc 0 24 0 r . . 8 8 8 0 . . 0 24 8 0 0 0 0 0 0 None 0x093 24 tc 0 24 0 r y . 8 8 8 0 . . 0 24 8 0 0 0 0 0 0 None 0x094 24 tc 0 24 0 r y . 8 8 8 0 . . 0 24 8 0 0 0 0 0 0 None 0x095 24 tc 0 32 0 r . . 8 8 8 8 . . 0 0 0 0 0 0 0 0 0 None 0x096 24 tc 0 32 0 r y . 8 8 8 8 . . 0 0 0 0 0 0 0 0 0 None 0x097 24 tc 0 32 0 r y . 8 8 8 8 . . 0 0 0 0 0 0 0 0 0 None 0x098 24 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Created attachment 50656 [details] xorg log
Created attachment 50657 [details] dmesg output (with boot option "drm.debug=0x06")
The question to be asked is "which driver is the system missing that controls the backlight?"
> The question to be asked is "which driver is the system missing that controls > the backlight?" I'm not sure how to answer that question. In gentoo I compiled my own kernel with the following modules built in : -> Device Drivers -> Graphics support -> Backlight & LCD device support -> Lowlevel LCD controls -> Platform LCD controls -> Generic (aka Sharp Corgi) Backlight Driver Here is my full kernel configuration : http://pastebin.com/ViRaaESF
As suggested here http://forums.gentoo.org/viewtopic-p-6797468.html#6797468 , adding "acpi_osi= " or "acpi_osi=Linux" to the kernel boot command line in grub, lets me adjust brightness with the keys provided on the laptop (Fn + left/right arrow). I added "acpi_osi=Linux" to grub so the machine now always boots with this parameter. It still boots to a blank screen, but I can press Fn + left arrow to switch the backlight on. Afterwards I can adjust the brightness with the keyboard controls. The gnome-power-manager based brightness control applet does not work however.
Can I provide any further information ? If I'm not correctly describing the problem, is there somewhere I can go for advice ?
Am I to understand that this is not a problem in the Intel driver ?
I think it is one of the backlight issues, similar to #41306 or #36823. There was one recent patch about a similar issue - http://lkml.org/lkml/2011/10/13/95 - could you try with it please?
Thanks for the feedback ! I patched my kernel with the suggested patch - same issue. I would guess from the description of the patch that this is not the issue here : the patch seems to concern the backlight being set to wrong brightness when it goes up (not any incapacity to adjust brightness). This bug however is different, I will resume the issue a little more concisely. If you just boot the system, the backlight is off and cannot be turned on with the brightness keys. If you can login without seeing what is on the screen, you can turn the backlight on with the command "setpci -s 00:02.0 F4.B=00", but it cannot be adjusted by keys or software, and will turn back off after lid shut, screensaver etc. Adding "acpi_osi=Linux" to the kernel boot command line lets you switch on and adjust the backlight with the brightness keys after boot, but it cannot be adjusted by software. On boot the backlight is always off. Annoying consequences : system cannot dim display when idle or when on battery. More banter here : http://dodonov.net/blog/2011/10/14/so-whats-been-up-with-intel-linux-graphics-this-week/
This bug seems to concern many people : google gives tens of threads/bugs for issues with the same symptoms. ie : https://bugs.launchpad.net/ubuntu/+source/linux/+bug/752165 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740893 http://markuswalther.com/tech/backlight.html
If it is a regression from previous kernel, I guess that the easiest way to get it solved by bisecting it to the patch which caused the problem.. @christobzr, as you can reproduce the problem consistently, could you do it for us please? Thanks!
*** Bug 44156 has been marked as a duplicate of this bug. ***
Btw, yes I will be happy to do the tests, however I do not currently have the machine...
Daniel is working on some patches to fix the backlight controller and is looking for victims^Wtesters.
Ok, I've created these patches, available at http://cgit.freedesktop.org/~danvet/drm/log/?h=backlight-confusion Git link is git://people.freedesktop.org/~danvet/drm backlight-confusion Please test them, thanks.
(In reply to comment #15) > Ok, I've created these patches, available at > http://cgit.freedesktop.org/~danvet/drm/log/?h=backlight-confusion > > Git link is git://people.freedesktop.org/~danvet/drm backlight-confusion > > Please test them, thanks. Updated patches and discussion at [1], also available in the "backlight" branch of [2]. Please test. [1] http://thread.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/13642 [2] git://gitorious.org/jani/drm.git
Please try i915.invert_brightness=1 module parameter with kernel version v3.5 or later, see if that fixes the brightness issue, and report 'lspci -vmmnn' if it does.
If someone finds the time to test and this is still an issue, please re-open
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