[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
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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
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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
1366x768
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
panel?
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
}}}
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Ticket URL: <http://dev.haiku-os.org/ticket/8457#comment:33>
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