Re: [BUG] simplefb not showing any output

On Fri, Sep 6, 2013 at 7:19 PM, David Herrmann [off-list ref] wrote:

On Fri, Sep 6, 2013 at 7:12 PM, Tom Gundersen [off-list ref] wrote:

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On Fri, Sep 6, 2013 at 6:57 PM, David Herrmann [off-list ref] wrote:

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( 2 more mails and you might get the fbdev ML right ;) )

Modern technology...

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- Is CONFIG_FB_EFI enabled? If not, please enable it and try again
(hint: CONFIG_FB_VESA doesn't hurt either)

FB_EFI was enabled, FB_VESA was not, but I'll enable it. Out of
interest, how could this affect the situation? If I understand
correctly these drivers won't be loaded as long as simple-framebuffer
is created, or am I missing something?

In case you disable X86_SYSFB vesafb might still be used (I wasn't
sure you used efifb). And there might be some nasty Kconfig-select
logic that I overlooked (like FB_BOOT_VESA_SUPPORT).. Just to be sure.

Ok. All is now enabled and the behavior is the same.

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- Could you try the _same_ kernel config but disable CONFIG_X86_SYSFB.
This will avoid creating simple-fb devices and instead load efifb
again. Does efifb work? Does efifb print the same offsets as your
simplefb printk()?

Yeah, efifb works fine, I'll double-check everything and note down the offsets.

Just to be clear, efifb still with the new x86-sysfb infrastructure
works? Because I moved some efifb quirks from efifb.c to
x86/kernel/sysfb_efi.c. So even with CONFIG_X86_SYSFB=n the situation
is still different from pre-3.12.

Turns out I must have messed up my initial testing (maybe I only
tested with an old kernel on efifb). With the current kernel both
X86_SYSFB=y (i.e., simplefb) and X86_SYSFB=n (i.e., efifb) are broken.
Only when I log in and "modprobe i915" do I get an fbcon, before that
the screen is black.

For the record here is the relevant dmesg outputs (they appear to be ok):

efifb: probing for efifb
efifb: framebuffer at 0x90000000, mapped to 0xffffc90009b00000, using
4224k, total 4224k
efifb: mode is 1366x768x32, linelengthV32, pages=1
efifb: scrolling: redraw
efifb: Truecolor: size=8:8:8:8, shift$:16:8:0

simple-framebuffer simple-framebuffer.0: framebuffer at 0x90000000,
mapped to 0xffffc90009b00000
simple-framebuffer simple-framebuffer.0: format¨r8g8b8,
mode66x768x32, linelengthV32
simple-framebuffer simple-framebuffer.0: fb0: simplefb registered!

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- Are you sure that it's an simplefb problem? Please make sure fbcon
is enabled (could you attach your dmesg output?). You could also try
SSH'ing into the machine and starting some fbdev program (like X with
xf86-video-fbdev installed). Or does fbcon with efifb work?

fbcon with efifb works fine (so I guess trying X is not necessary?).

Yeah, if fbcon+efifb works, no need to test X.

Scratch this, I'll have to do some more testing. I'll get back to you.

-t