I would like to increase screen backlight PWM frequency in Dell Inspiron 3593 with factory installed Ubuntu (this laptop, like many other Dell models, probably has only 200 Hz). I read that it can be done with software by installing Intel GPU tools and editing a proper register: link I installed these tools as described here: by running sudo apt-get update
and sudo apt-get install intel-gpu-tools
. However, when I run intel_reg read 0xC8254
, I get:
Warning: register spec not found in '/usr/share/intel-gpu-tools/registers'. Using builtin register spec.
(intel_reg:9325) intel-mmio-CRITICAL: Test assertion failure function intel_mmio_use_pci_bar, file ../../lib/intel_mmio.c:145:
(intel_reg:9325) intel-mmio-CRITICAL: Failed assertion: !(error != 0)
(intel_reg:9325) intel-mmio-CRITICAL: Last errno: 13, Permission denied
(intel_reg:9325) intel-mmio-CRITICAL: Couldn't map MMIO region
Stack trace:
#0 [_init+0x137c7]
#1 [_init+0xe620]
#2 [_init+0xe6d1]
#3 [_init+0x25cf]
#4 [_init+0xf7d]
#5 [__libc_start_main+0xe7]
#6 [_init+0x1002]
Test (null) failed.
**** DEBUG ****
(intel_reg:9325) intel-chipset-DEBUG: Test requirement passed: pci_dev
(intel_reg:9325) intel-mmio-CRITICAL: Test assertion failure function intel_mmio_use_pci_bar, file ../../lib/intel_mmio.c:145:
(intel_reg:9325) intel-mmio-CRITICAL: Failed assertion: !(error != 0)
(intel_reg:9325) intel-mmio-CRITICAL: Last errno: 13, Permission denied
(intel_reg:9325) intel-mmio-CRITICAL: Couldn't map MMIO region
(intel_reg:9325) igt-core-INFO: Stack trace:
(intel_reg:9325) igt-core-INFO: #0 [_init+0x137c7]
(intel_reg:9325) igt-core-INFO: #1 [_init+0xe620]
(intel_reg:9325) igt-core-INFO: #2 [_init+0xe6d1]
(intel_reg:9325) igt-core-INFO: #3 [_init+0x25cf]
(intel_reg:9325) igt-core-INFO: #4 [_init+0xf7d]
(intel_reg:9325) igt-core-INFO: #5 [__libc_start_main+0xe7]
(intel_reg:9325) igt-core-INFO: #6 [_init+0x1002]
**** END ****
FAIL (-1.000s)
Could you please tell me if it's possible in this laptop and what's the correct register?