[haiku-bugs] Re: [Haiku] #8457: Blank screen after boot on Radeon Mobility 4670 HD

  • From: "kallisti5" <trac@xxxxxxxxxxxx>
  • Date: Mon, 01 Jul 2013 21:17:33 -0000

#8457: Blank screen after boot on Radeon Mobility 4670 HD
   Reporter:  kvark                       |      Owner:  kallisti5
       Type:  bug                         |     Status:  new
   Priority:  normal                      |  Milestone:  R1
  Component:  Drivers/Graphics/radeon_hd  |    Version:  R1/Development
 Resolution:                              |   Keywords:  blank radeon
 Blocked By:                              |   Blocking:  7662
Has a Patch:  0                           |   Platform:  x86

Comment (by kallisti5):

 Well, there ya go.  Looks like a bug in your laptop's bios :)

 We think DRM looks for an EDID from the LVDS panel before going to the
 LVDS_Into table. That is likely the difference.

 21:08 <kallisti5> Good morning.  Super quick question.  Do you know the
 case to ignore the AtomBIOS LVDS_Info off the top of your head?
 21:09 <AMD> it should always be correct
 21:09 <kallisti5> I have a user with a Radeon HD Mobility 4670. usHActive
 is 1400 and usVActice is 1050. however the native resolution of the lcd is
 21:09 <kallisti5> hmm
 21:10 <AMD> is it a mac?
 21:10 <kallisti5> I did see the LVDS patch table, but it doesn't seem to
 exist in the later table version (1.2)
 21:10 <kallisti5> not that i'm aware of... good question though
 21:10 <AMD> or did the user hack their system and install a non-standard
 21:10 <kallisti5> nope. "MSI EX625 laptop"
 21:11 <kallisti5> well.. vesa has the correct perferred mode
 21:11 <kallisti5> KERN: Additional Video Mode (1366x768@59Hz):
 21:11 <AMD> if the panel has an EDID you can check that first
 21:11 <kallisti5> I thought lvds didn't have edid?
 21:11 <AMD> usually does
 21:11 <AMD> only on really old laptops
 21:12 <AMD> does it not
 21:12 <AMD> the sbios usually patches the vbios LCDInfo table with the
 values from the EDID at boot
 21:12 <kallisti5> ah. ok.  that helps :D  We can check for edid, else look
 for lvds_info
 21:12 <AMD> which is how the values get there
 21:12 <kallisti5> aah.  It maybe a quirk
 21:13 <AMD> could be a funky oem bios
 21:13 <kallisti5> 99% of the time it's been fine... just this one machine
 21:13 <kallisti5> thanks :)
 21:13 <AMD> np

Ticket URL: <http://dev.haiku-os.org/ticket/8457#comment:33>
Haiku <http://dev.haiku-os.org>
Haiku - the operating system.

Other related posts: