Hi Guys,
someone might be interested... i have a old HP 250 G4 with a i3. but it had a terrible HD screen... so was interested in retrofitting the laptop with a full HD panel. (have 16G RAM and a SSD drive, so the laptop is definitely not a throw away candidate).
there is no standard for embeded displayport pinouts, there is just a recommendation by VESA. but i believe no-one is stupid enough to create a custom pinout for the eDP 30pin connector.
so started to investigate... and sure enough the pinout of the cable in the laptop looked pretty much like the vesa pinout recommendation.. and the connector had wires for both data lanes (FHD needs 2 lanes, HD is happy with single lane)
all the forums were full of answers like - no it won't work, FHD works on HDMI out but will not work on the eDP port, chances are next to zero, good luck with that... etc...
but eDP signaling is the same as DP + brightness controll...so why it shouldn't work ? if the GPU can do FHD over one port (HDMI) surely it does over another port (DP) ... if the cable has the wires for 2 lanes it should work.
so took the "gamble" (was 95% sure it works) and ordered a new FHD panel which had it's mounting holes similar to the original panel and had the connector roughly in the same place. turned out mechanicaly the panel was a perfect match (mounting holes, bezel.. spot on)... and of course it works
exact laptop model : HP 250 G4 , SKU Number: M9S80EA#BCM
retrofitted IPS panel: NV156FHM-N48 V8.2
hope someone finds this useful