I have an Acer Aspire ES1-531-P8JN. It has the Intel N3700 CPU with integrated graphics. I have the problem that the video driver i915 does not seem to work in Debian Jessie 8.3.0, even though it does work on (L)Ubuntu 15.10. I am concerned about this, because I'd like the program xbacklight to work on Debian, too, because I actually prefer Debian over Ubuntu, but had to switch to Lubuntu, because my eyes got really strained.Here is what I get for sudo lshw -c video in Debian:  *-display UNCLAIMED       description: VGA compatible controller       product: Intel Corporation       vendor: Intel Corporation       physical id: 2       bus info: pci@0000:00:02.0       version: 21       width: 64 bits       clock: 33MHz       capabilities: pm msi vga_controller bus_master cap_list       configuration: latency=0       resources: memory:90000000-90ffffff memory:80000000-8fffffff ioport:2000(size=64)And here is what I get in Lubuntu:  *-display       description: VGA compatible controller       product: Intel Corporation       vendor: Intel Corporation       physical id: 2       bus info: pci@0000:00:02.0       version: 21       width: 64 bits       clock: 33MHz       capabilities: pm msi vga_controller bus_master cap_list rom       configuration: driver=i915 latency=0       resources: irq:312 memory:90000000-90ffffff memory:80000000-8fffffff ioport:2000(size=64)lsmod | grep i915 in Debian gives me:i915                           837175  0 drm_kms_helper         49210        1   i915drm                             249955  2   i915,drm_kms_helperi2c_algo_bit                12751       1   i915video                            18096      2   i915,acer_wmibutton                      12944       1   i915i2c_core                    46012       7   drm,i915,i2c_hid,drm_kms_helper,i2c_algo_bit,v4l2_common,videodevAnd in Lubuntu:i915                       1130496     4i2c_algo_bit                16384       1    i915drm_kms_helper          126976      1    i915drm                             356352      5   i915,drm_kms_helpervideo                           ls 36864    2   i915,acer_wmiAlso there is no entry in /sys/class/backlight in Debian, while in Lubuntu I have intel_backlight. I read somewhere that when there is no entry in /sys/class/backlight it means that the Linux kernel thinks that the display is a very old one where there is a physical brightness switch. But I don't think the kernel that Debian and Ubuntu use are that different.Please help me get xbacklight to work on Debian. Thanks!Edit: I add the error messages in dmesg:Lubuntu:[    0.182944] ACPI Error: No handler for Region [RAM_] (ffff88017b4b8558) [EmbeddedControl] (20150619/evregion-163)[    0.182955] ACPI Error: Region EmbeddedControl (ID=3) has no handler (20150619/exfldio-297)[    0.182966] ACPI Error: Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._REG] (Node ffff88017b4b9208), AE_NOT_EXIST (20150619/psparse-536)[    0.183081] ACPI Error: No handler for Region [RAM_] (ffff88017b4b8558) [EmbeddedControl] (20150619/evregion-163)[    0.183089] ACPI Error: Region EmbeddedControl (ID=3) has no handler (20150619/exfldio-297)[    0.183097] ACPI Error: Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._REG] (Node ffff88017b4b9208), AE_NOT_EXIST (20150619/psparse-536)[    0.243103] acpi PNP0A08:00: _OSC failed (AE_ERROR); disabling ASPM[    1.971340] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[    2.356840] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[    3.270826] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[   16.051457] EXT4-fs (sda5): re-mounted. Opts: errors=remount-ro[  110.693938] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[  116.909911] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[  118.610041] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[  221.721939] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request[  223.091774] [drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS requestDebian:[    0.200280] ACPI Error: No handler for Region [RAM_] (ffff88017f056938) [EmbeddedControl] (20140424/evregion-163)[    0.200290] ACPI Error: Region EmbeddedControl (ID=3) has no handler (20140424/exfldio-297)[    0.200300] ACPI Error: Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._REG] (Node ffff88017f057f18), AE_NOT_EXIST (20140424/psparse-536)[    0.200412] ACPI Error: No handler for Region [RAM_] (ffff88017f056938) [EmbeddedControl] (20140424/evregion-163)[    0.200419] ACPI Error: Region EmbeddedControl (ID=3) has no handler (20140424/exfldio-297)[    0.200426] ACPI Error: Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._REG] (Node ffff88017f057f18), AE_NOT_EXIST (20140424/psparse-536)[    0.389651] acpi PNP0A08:00: _OSC failed (AE_ERROR); disabling ASPM[    8.578880] EXT4-fs (dm-0): re-mounted. Opts: errors=remount-ro[    9.899828] usb 1-5.1: Direct firmware load failed with error -2[    9.902636] ath3k: probe of 1-5.1:1.0 failed with error -12According to this site, not having any entries in /sys/class/backlight might also mean problems with the ACPI backlight driver. There were some error messages regarding ACPI in dmesg, but unfortunately not only in Debian, but also in Ubuntu. In Ubuntu backlight control works, though.Edit2: The kernel version of Debian 8.3.0 is 3.16.0-4-amd64, while the kernel of Lubuntu 15.10 is of a newer version 4.2.0-27-generic. I wonder if that makes a difference...
How to make video driver work in Debian Jessie
drivers;backlight