The model of my laptop is Acer V7-481 which comes with an [B]i3-3227U[/B] CPU and [B]NO[/B] graphic card. When I was installing ubuntu 12.04 for the first time, the laptop booted up in a black screen The only solution to this is to add a boot parameter nomodeset or something to disable the KMS. Other solutions I found are useless, including acpi related and adjust the backlight using shortcuts etc. Now, my laptop can ONLY boot with NOMODESET but I don't think the integrated graphic card is functioning normally. NOTE:This happens on distros that doesn't have a GUI 1. I cannot connect to a second monitor via HDMI and Display Port 2. unity is running in 2d mode 3. can't use 3d hardware acceleration 4. cannot change backlight with shortcuts The back light is on without nomodeset and can be adjusted by keyboard shortcut however, with nomodest, I can't change the back light. out put of `uname -a` `Linux v7 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux` out put of `lshw -c video` ``` *-display UNCLAIMED description: VGA compatible controller product: 3rd Gen Core processor Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 09 width: 64 bits clock: 33MHz capabilities: msi pm vga_controller bus_master cap_list configuration: latency=0 resources: memory:c0000000-c03fffff memory:b0000000-bfffffff ioport:3000(size=64) ```
What we need is the drm.debug=6 dmesg (append drm.debug=6 to the kernel command line in grub) for the faulty boot with KMS enabled. Please also use a recent kernel, 3.14 or preferrably a 3.15-rc to be closer to upstream wrt bugfixes.
Created attachment 99765 [details] dmsg with drm.debug=6 This is a text file that contains the information you required.
Please try video.use_native_backlight=1 module parameter.
(In reply to comment #3) > Please try video.use_native_backlight=1 module parameter. Well after add this to grub, I still can't get it work without nomodeset. Actually, this parameter disabled the shortcuts that was able to change the backlight without nomodeset
If you drop all the extra kernel/module parameters, incl. nomodeset, what do you have in /sys/class/backlight? Can you enable backlight by echoing the value in max_brightness to brightness? Is the backlight the only thing that fails?
(In reply to comment #5) > If you drop all the extra kernel/module parameters, incl. nomodeset, what do > you have in /sys/class/backlight? Can you enable backlight by echoing the > value in max_brightness to brightness? Is the backlight the only thing that > fails? well, without nomodeset I can see nothing but a grey screen, the backlight of which can be adjusted. However, with nomodeset, I can't adjust the backlight
(In reply to comment #6) > (In reply to comment #5) > > If you drop all the extra kernel/module parameters, incl. nomodeset, what do > > you have in /sys/class/backlight? Can you enable backlight by echoing the > > value in max_brightness to brightness? Is the backlight the only thing that > > fails? > > well, without nomodeset I can see nothing but a grey screen, the backlight > of which can be adjusted. > However, with nomodeset, I can't adjust the backlight Ah. We don't support nomodeset for your hardware, so the backlight is not the issue. The issue is getting something on screen.
(In reply to comment #7) > (In reply to comment #6) > > (In reply to comment #5) > > > If you drop all the extra kernel/module parameters, incl. nomodeset, what do > > > you have in /sys/class/backlight? Can you enable backlight by echoing the > > > value in max_brightness to brightness? Is the backlight the only thing that > > > fails? > > > > well, without nomodeset I can see nothing but a grey screen, the backlight > > of which can be adjusted. > > However, with nomodeset, I can't adjust the backlight > > Ah. We don't support nomodeset for your hardware, so the backlight is not > the issue. The issue is getting something on screen. So, does this mean that I have to wait for another update to get my graphic to work normally? I know the backlight is not an issue and I don't care much about that, but using nomodeset is the only way to get something on screen, in which way the graphic is pretty slow.
(In reply to comment #8) > So, does this mean that I have to wait for another update to get my graphic > to work normally? > I know the backlight is not an issue and I don't care much about that, but > using nomodeset is the only way to get something on screen, in which way the > graphic is pretty slow. Now we'll need to debug why there's nothing on screen. The first suggestion from Chris was to try a recent kernel, preferrably 3.15-rc8, and paste the dmesg with drm.debug=0xe module parameter running that.
(In reply to comment #9) > dmesg with drm.debug=0xe module parameter running that. or drm.debug=6 as long as the kernel is new.
Created attachment 100362 [details] dmesg without nomodeset on kernel 3.15-rc8
(In reply to comment #11) > Created attachment 100362 [details] > dmesg without nomodeset on kernel 3.15-rc8 Hi, I updated the kernel to 3.15-rc8(which can't fix this problem) and posted the dmesg info as an attachment. I hope that helps.
Well, just FYI, I've updated the kernel to the most up-to-date beta version, and this problem still exists
I updated the kernel to 3.18 rc4. And now it works fine. I didn't try 3.17 though
Thanks a lot for this bug report and the testing feedback, closing this one. If you want you could attempt a reverse bisect and if it's just a small patch we could backport it. But given that 3.18 will release soonish probably not worth the effort.
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