Screen flashes once at boot...How to get rid of it

LegionOfHell · Post by **LegionOfHell** » Thu May 09, 2019 11:25 pm

When I turn my laptop on and choose "Gentoo GNU/Linux" from the Grub menu and shortly after the "loading linux 4.19-27 gentoo-r1" screen, during the screen with pictures of Penguins at the top, My screen flashes once...How do I remove this flash ?

The Doctor · Post by **The Doctor** » Thu May 09, 2019 11:46 pm

The flash is the kernel refreshing the driver. Build in the driver into the kernel instead of using a module if possible.

LegionOfHell · Post by **LegionOfHell** » Thu May 09, 2019 11:47 pm

how do I figure out which driver it is ?

LegionOfHell · Post by **LegionOfHell** » Thu May 09, 2019 11:56 pm

do you mean these:

Device Drivers --->
Generic Driver Options --->
-*- Userspace firmware loading support
[*] Include in-kernel firmware blobs in kernel binary
(i915/skl_dmc_ver1_26.bin) External firmware blobs to build into the kernel binary
(/lib/firmware) Firmware blobs root directory

The Doctor · Post by **The Doctor** » Thu May 09, 2019 11:58 pm

The driver depends on your video card. A good read through the Gentoo Handbook will tell you how to find it.

If you are a genkernel user you will need to use the --menuconfig option to customize the kernel.

The Doctor · Post by **The Doctor** » Fri May 10, 2019 12:01 am

LegionOfHell wrote:do you mean these:

Device Drivers --->
Generic Driver Options --->
-*- Userspace firmware loading support
[*] Include in-kernel firmware blobs in kernel binary
(i915/skl_dmc_ver1_26.bin) External firmware blobs to build into the kernel binary
(/lib/firmware) Firmware blobs root directory

No, the options are under Device Drivers -> Graphics support

LegionOfHell · Post by **LegionOfHell** » Fri May 10, 2019 12:17 am

Here are the photos of stuff under Device Drivers--->Graphics support

https://ibb.co/9bG0LMT
https://ibb.co/6Fxth2c

they are all built in ...

Also, here is the GPU information :

https://ibb.co/tLZqrrf

LegionOfHell · Post by **LegionOfHell** » Fri May 10, 2019 12:37 am

Also, should I worry about kernel messages ? should I read the log at /etc/log/messages and read through it searching for errors ?

ian.au · Post by **ian.au** » Fri May 10, 2019 1:54 am

LegionOfHell wrote:Also, should I worry about kernel messages ? should I read the log at /etc/log/messages and read through it searching for errors ?

Well that qualifies as a new topic really... but the level of 'worry' attached to logs is really only relevant to your threat profile.

The log location and format depends on your choice of init system, then which logger you have installed, but they'll be under /var/. If you're on a default install with openRC you choose from a few options here: https://wiki.gentoo.org/wiki/Handbook:A ... tion/Tools. On desktops I use metalog and grep through the logs for warn or err daily, that's plenty. If you're running a server of any sort then logs take on a whole new level of significance.

With systemd you get logging via journalctl and whatever else you choose to install from the above tools, they're not exclusive, either way following the handbook should have taken you through this.

Kernel messages are important, especially when setting up / customising and debugging a new system, or to start debugging when problems occur. Some of them are more important than others, it just takes a bit of time, research and experience to work out

Code: Select all

man dmesg

and

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dmesg --level=err,warn

to quieten the noise.

LegionOfHell · Post by **LegionOfHell** » Fri May 10, 2019 3:41 am

oh thanks for that command...it is handy...How about the flash that i get at boot ?

szatox · Post by **szatox** » Fri May 10, 2019 7:08 am

How about the flash that i get at boot ?

The Doctor already told you: reconfigure your kernel so the video driver is builtin rather than a module.
You can use 'lspci -k' to find out what kernel driver is in use.
There are not a lot of popular grapic drivers though, so you probably already know what you need though.

LegionOfHell · Post by **LegionOfHell** » Fri May 10, 2019 5:54 pm

but my drivers are built in...I just pasted the photos...

skellr · Post by **skellr** » Sat May 11, 2019 6:43 am

I think it's flashing when it switches framebuffer drivers. It will switch between them if you have multiple configured. I'm not sure if it keeps choosing a "better" driver as it progresses through the sequence or not.

I would just enable one, I just use EFI framebuffer. simple fb or intelfb might be good also. not sure which one is "best".

skellr · Post by **skellr** » Sat May 11, 2019 6:39 pm

One thing that bothered me about intelfb is that it wouldn't show "early printk" like EFI fb would. it would only initialize and start displaying near the end of the kernel output, not far before init. I'm sure there is a better/proper name for it... Maybe i'm just anal but I like to see it. The human eye can still notice when something is off, even when output is scrolling by so fast. At least on a desktop/laptop, servers have logs.

LegionOfHell · Post by **LegionOfHell** » Sat May 11, 2019 10:03 pm

if you mean :

Device Drivers --->
Graphics support --->
Frame Buffer Devices --->

I have all options under *** Frame buffer hardware drivers *** unset except "EFI-based Framebuffer Support"

because according to the xorg guide, I have to set it if I am using UEFI...here is a photo : https://ibb.co/p2n1bfL

I also have this black lines appearing as I scroll down in menuconfig...note that I have not installed xorg yet...

skellr · Post by **skellr** » Sat May 11, 2019 10:24 pm

LegionOfHell wrote:if you mean :

Device Drivers --->
Graphics support --->
Frame Buffer Devices --->

I have all options under *** Frame buffer hardware drivers *** unset except "EFI-based Framebuffer Support"

because according to the xorg guide, I have to set it if I am using UEFI...here is a photo : https://ibb.co/p2n1bfL

I also have this black lines appearing as I scroll down in menuconfig...note that I have not installed xorg yet...

Yes, it usually flashes when it switches display drivers. it usually switches between fb drivers the most during the boot.

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dmesg | grep -i switching

I've noticed the black likes in the kernel menuconfig also. It goes away after a while. I suspect it has something to do with ncurses. once you get further along and have recompiled things it will go away.

I'm not a "guru" and can't tell you why it happens, just that it should pass. Exept for the flashing issue.

Good luck.

LegionOfHell · Post by **LegionOfHell** » Sat May 11, 2019 10:49 pm

dmesg | grep -i switching :

https://ibb.co/ThwJyQf

what is the solution ? should I turn off the EFI framebuffer support ? will that cause any problems ?

ian.au · Post by **ian.au** » Sat May 11, 2019 11:17 pm

Turning off efi framebuffer support = no console during efi boot, I doubt you want that.

What's calling the switch to intelfb? Maybe try turning off the boot logo in config?

skellr · Post by **skellr** » Sat May 11, 2019 11:52 pm

LegionOfHell wrote: what is the solution ? should I turn off the EFI framebuffer support ? will that cause any problems ?

I think you could. I doubt you will see the initial kernel messages "printk" like you would with EFI framebuffer. It will probably just show you the last few lines before the init system starts. almost like you passed quiet as a kernel parameter. intelfb or inteldrmfb should then kick in and start displaying. but there will be a delay before it does.

I think inteldrmfb is a bonus "gift" when using intel video drivers, at least for users.

Not sure how to disable it.

I don't think it's a module so module.blacklist won't work... maybe there is a kernel parameter?

skellr · Post by **skellr** » Sun May 12, 2019 12:02 am

Try this... maybe you can tell it to use EFI fb instead. as a kernel parameter.

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video=efifb

Maybe it will stick with it and not switch?

LegionOfHell · Post by **LegionOfHell** » Sun May 12, 2019 12:21 am

"What's calling the switch to intelfb? Maybe try turning off the boot logo in config? "

how do i figure that out ?

skellr, I will try that solution last...

How about nomodeset ?

bammbamm808 · Post by **bammbamm808** » Sun May 12, 2019 2:03 am

LegionOfHell wrote:"What's calling the switch to intelfb? Maybe try turning off the boot logo in config? "

how do i figure that out ?

skellr, I will try that solution last...

How about nomodeset ?

Google these terms. The internet is full of documentation on the things they refer to. Then, if you have questions after making an attempt to educate yourself, ask someone. This is the best approach to linux.

The Doctor · Post by **The Doctor** » Sun May 12, 2019 4:27 am

A fundamental issue here is that it is that it is probably impossible to completely eliminate the mode shifts. The initial boot comes from a bare bones system that doesn't (and can't) include sophisticated video drivers. There just is not enough space. By ensuring an appropriate driver is available in the kernel you can switch to that as soon as the kernel takes over. Genkernel complicates this by having too many drivers and not having the available right away. My system changes resolutions three times during bootup. Once after displaying the EUFI splash screen, once when displaying the (EUFI) bootloader, and once when the kernel takes over. The first two cannot be helped as I have no control over the code being run. The third is the code I do control setting the resolution I do want. What should be controllable is removing a generic driver that is then switched to a specific one during the boot process and that one would cause the problem you described.

Where this process can become impossible is for proprietary drivers used by AMD and NIVIDA. They require the closed source driver be loaded as a module.

A custom kernel is the best way forward if you want to tune the system. It sounds like your experiencing inefficiencies that would take quite a while to chase down since genkernel is bloated by design. It is a general purpose kernel that will work just about anywhere with just about any hardware. This means it has just about everything available and no memory about what it actually needs so it ends up trying everything. It sounds like this is annoying to you, so learning how to make a custom kernel is probably your next step.

LegionOfHell · Post by **LegionOfHell** » Thu May 16, 2019 7:21 pm

I tried :

GRUB_CMDLINE_LINUX_DEFAULT="video=inteldrmfb:off,efifb:off"
GRUB_CMDLINE_LINUX_DEFAULT="video=inteldrmfb:off,efifb"
GRUB_CMDLINE_LINUX_DEFAULT="video=inteldrmfb,efifb:off"
GRUB_CMDLINE_LINUX_DEFAULT="video=efifb"

and none of these resolve the issue..

with GRUB_CMDLINE_LINUX_DEFAULT="video=inteldrmfb,efifb:off"

I don't get the "switching to inteldrmfb" message..

GRUB_CMDLINE_LINUX_DEFAULT="nomodeset" works beautifully though ...

Post by **pjp** » Thu May 16, 2019 7:39 pm

Moved from Installing Gentoo to Other Things Gentoo as this is a post-installation issue.

Does the referenced material in [topic=1096390]Flicker Free Boot[/topic] help?