Intel Squaring Away "Hours of Battery Life" Feature For New Notebooks On Linux
As confirmed via patches earlier this month for implementing the support in Intel's DRM kernel driver, HOBL is for "Hours of Battery Life." This is a power-savings feature where supported laptops can take advantage of an optimized voltage swing table that uses less power in conjunction with motherboards and embedded DisplayPort (eDP) panels able to operate at the lower voltage.
This basically amounts to allowing select eDP panels driven by Intel Gen12+ graphics to ideally operate at a lower voltage. If anything fails from the driver side, it will fall-back to the original voltage table. But as the driver is parsing the new voltage table, just how much lower the voltages will be on "HOBL" setups remains to be seen... If it can actually equate to extra "hours of battery life" it will be impressive but at this stage it remains to be seen.
When looking to find more on Intel HOBL, there is this patent application from 2019 concerning "Dynamic sleep for a display panel." That application notes, "the dynamic sleep state feature can result in significant CPU/SoC power savings (e.g., an increase of 20-30% in CPU/SoC power saving)...For HoBL web browsing, the DE read BW can drop 60% and the eDP IO BW can drop 30%. For HoBL productivity, there can be a 80% drop in both the DE read BW and the eDP IO BW."
So we'll see how this Intel HOBL feature turns out once Tiger Lake laptops begin shipping and if it does indeed equate to "hours of battery life", which thanks to the nature of open-source can be easily verified by reverting these patches once merged.
The Intel HOBL patches for Linux are still under review but could be mainlined as soon as the Linux 5.9 cycle kicks off in August.
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