bugGNU GRUB - Bugs: bug #50911, i386-pc: ability to probe extra...


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bug #50911: i386-pc: ability to probe extra VBE modes

Submitted by:  felix <felix_s>
Submitted on:  Tue 02 May 2017 08:27:04 AM UTC  
Category: User InterfaceSeverity: Major
Priority: 5 - NormalItem Group: Feature Request
Status: NonePrivacy: Public
Assigned to: NoneOriginator Name: 
Open/Closed: OpenRelease: 
Release: Git masterReproducibility: Every Time
Planned Release: None

Tue 02 May 2017 08:27:04 AM UTC, original submission:

Some VBE implementations may fail to advertise the availability of all supported video modes via the interrupt call 0x10/ax=0x4f00. I used to have a laptop with Intel integrated graphics which did just that: mode 0x17d/0x17e/0x17f set the highest possible resolution on the available display (8bpp, 16bpp, 32bpp respectively), but I only found it out by brute-forcing queries to the interrupt 0x10/ax=0x4f01 call.

I can work this around by patching the video BIOS (that is, unlocking writes to the [0xc0000, 0xcffff] RAM range, patching the modes list and locking the range again), but this is quite ugly, hardware-specific and potentially dangerous. I'd rather would have set a variable in GRUB which would make the vbe module probe modes of my choosing in addition to (or maybe even instead of?) the ones returned from the interrupt 0x10/ax=0x4f00 call.

felix <felix_s>


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