[PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[WANG Chao]

Now only 50plymouth module can pull in 50drm and that's very limited.
Because KMS capable drm drivers are much needed in initrd to have a
frame buffer console on the screen.

Particularly, when building kdump initrd, plymouth module is omitted,
but drm is necessary to setup a working screen for one sitting in front
of a monitor.

Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 modules.d/50drm/module-setup.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
index bf33c5b..648e8f4 100644
--- a/modules.d/50drm/module-setup.sh
+++ b/modules.d/50drm/module-setup.sh
@@ -3,6 +3,10 @@
 # ex: ts=8 sw=4 sts=4 et filetype=sh
 
 check() {
+    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
+        return 0
+    fi
+
     return 255
 }
 
-- 
1.8.2.1

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[Harald Hoyer]

On 05/24/2013 10:22 AM, WANG Chao wrote:
> Now only 50plymouth module can pull in 50drm and that's very limited.
> Because KMS capable drm drivers are much needed in initrd to have a
> frame buffer console on the screen.
> 
> Particularly, when building kdump initrd, plymouth module is omitted,
> but drm is necessary to setup a working screen for one sitting in front
> of a monitor.
> 
> Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  modules.d/50drm/module-setup.sh | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
> index bf33c5b..648e8f4 100644
> --- a/modules.d/50drm/module-setup.sh
> +++ b/modules.d/50drm/module-setup.sh
> @@ -3,6 +3,10 @@
>  # ex: ts=8 sw=4 sts=4 et filetype=sh
>  
>  check() {
> +    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
> +        return 0
> +    fi
> +
>      return 255
>  }
>  
> 

Hmm, why not let the kdump module depend on drm?

depends() {
    echo drm
}

Anyway, do we really need drm for a simple console? Those drivers are really
really big and take a long time to load and initialize?

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[Dave Young]

On 05/28/2013 08:09 PM, Harald Hoyer wrote:
> On 05/24/2013 10:22 AM, WANG Chao wrote:
>> Now only 50plymouth module can pull in 50drm and that's very limited.
>> Because KMS capable drm drivers are much needed in initrd to have a
>> frame buffer console on the screen.
>>
>> Particularly, when building kdump initrd, plymouth module is omitted,
>> but drm is necessary to setup a working screen for one sitting in front
>> of a monitor.
>>
>> Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> ---
>>  modules.d/50drm/module-setup.sh | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
>> index bf33c5b..648e8f4 100644
>> --- a/modules.d/50drm/module-setup.sh
>> +++ b/modules.d/50drm/module-setup.sh
>> @@ -3,6 +3,10 @@
>>  # ex: ts=8 sw=4 sts=4 et filetype=sh
>>  
>>  check() {
>> +    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
>> +        return 0
>> +    fi
>> +
>>      return 255
>>  }
>>  
>>
> 
> Hmm, why not let the kdump module depend on drm?

If you do not like it we can consider add it to kdump module..

> 
> depends() {
>     echo drm
> }
> 
> Anyway, do we really need drm for a simple console? Those drivers are really
> really big and take a long time to load and initialize?

It's a little awkward, after kernel crashing suppose 1st kernel is in
kms mode, it can not reset to nomodeset, so screen will keep black.

There's no such issue in normal initramfs because bios always reset
devices for us.

> 


-- 
Thanks
Dave

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[WANG Chao]

On 05/29/13 at 10:45am, Dave Young wrote:
> On 05/28/2013 08:09 PM, Harald Hoyer wrote:
> > On 05/24/2013 10:22 AM, WANG Chao wrote:
> >> Now only 50plymouth module can pull in 50drm and that's very limited.
> >> Because KMS capable drm drivers are much needed in initrd to have a
> >> frame buffer console on the screen.
> >>
> >> Particularly, when building kdump initrd, plymouth module is omitted,
> >> but drm is necessary to setup a working screen for one sitting in front
> >> of a monitor.
> >>
> >> Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> >> ---
> >>  modules.d/50drm/module-setup.sh | 4 ++++
> >>  1 file changed, 4 insertions(+)
> >>
> >> diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
> >> index bf33c5b..648e8f4 100644
> >> --- a/modules.d/50drm/module-setup.sh
> >> +++ b/modules.d/50drm/module-setup.sh
> >> @@ -3,6 +3,10 @@
> >>  # ex: ts=8 sw=4 sts=4 et filetype=sh
> >>  
> >>  check() {
> >> +    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
> >> +        return 0
> >> +    fi
> >> +
> >>      return 255
> >>  }
> >>  
> >>
> > 
> > Hmm, why not let the kdump module depend on drm?
> 
> If you do not like it we can consider add it to kdump module..

So now if I build initrd w/o plymouth, I will not have frame buffer
console in initrd. That looks more like a general issue to me.

WANG Chao

> 
> > 
> > depends() {
> >     echo drm
> > }
> > 
> > Anyway, do we really need drm for a simple console? Those drivers are really
> > really big and take a long time to load and initialize?
> 
> It's a little awkward, after kernel crashing suppose 1st kernel is in
> kms mode, it can not reset to nomodeset, so screen will keep black.
> 
> There's no such issue in normal initramfs because bios always reset
> devices for us.
> 
> > 
> 
> 
> -- 
> Thanks
> Dave
> 
> 

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[Harald Hoyer]

On 05/29/2013 08:57 AM, WANG Chao wrote:
> On 05/29/13 at 10:45am, Dave Young wrote:
>> On 05/28/2013 08:09 PM, Harald Hoyer wrote:
>>> On 05/24/2013 10:22 AM, WANG Chao wrote:
>>>> Now only 50plymouth module can pull in 50drm and that's very limited.
>>>> Because KMS capable drm drivers are much needed in initrd to have a
>>>> frame buffer console on the screen.
>>>>
>>>> Particularly, when building kdump initrd, plymouth module is omitted,
>>>> but drm is necessary to setup a working screen for one sitting in front
>>>> of a monitor.
>>>>
>>>> Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>>> ---
>>>>  modules.d/50drm/module-setup.sh | 4 ++++
>>>>  1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
>>>> index bf33c5b..648e8f4 100644
>>>> --- a/modules.d/50drm/module-setup.sh
>>>> +++ b/modules.d/50drm/module-setup.sh
>>>> @@ -3,6 +3,10 @@
>>>>  # ex: ts=8 sw=4 sts=4 et filetype=sh
>>>>  
>>>>  check() {
>>>> +    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
>>>> +        return 0
>>>> +    fi
>>>> +
>>>>      return 255
>>>>  }
>>>>  
>>>>
>>>
>>> Hmm, why not let the kdump module depend on drm?
>>
>> If you do not like it we can consider add it to kdump module..
> 
> So now if I build initrd w/o plymouth, I will not have frame buffer
> console in initrd. That looks more like a general issue to me.
> 
> WANG Chao

Do we really need a fb console?
If there is a valid reason, I will change "return 255" to "return 0".

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[WANG Chao]

On 05/29/13 at 11:44am, Harald Hoyer wrote:
> On 05/29/2013 08:57 AM, WANG Chao wrote:
> > On 05/29/13 at 10:45am, Dave Young wrote:
> >> On 05/28/2013 08:09 PM, Harald Hoyer wrote:
> >>> On 05/24/2013 10:22 AM, WANG Chao wrote:
> >>>> Now only 50plymouth module can pull in 50drm and that's very limited.
> >>>> Because KMS capable drm drivers are much needed in initrd to have a
> >>>> frame buffer console on the screen.
> >>>>
> >>>> Particularly, when building kdump initrd, plymouth module is omitted,
> >>>> but drm is necessary to setup a working screen for one sitting in front
> >>>> of a monitor.
> >>>>
> >>>> Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> >>>> ---
> >>>>  modules.d/50drm/module-setup.sh | 4 ++++
> >>>>  1 file changed, 4 insertions(+)
> >>>>
> >>>> diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
> >>>> index bf33c5b..648e8f4 100644
> >>>> --- a/modules.d/50drm/module-setup.sh
> >>>> +++ b/modules.d/50drm/module-setup.sh
> >>>> @@ -3,6 +3,10 @@
> >>>>  # ex: ts=8 sw=4 sts=4 et filetype=sh
> >>>>  
> >>>>  check() {
> >>>> +    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
> >>>> +        return 0
> >>>> +    fi
> >>>> +
> >>>>      return 255
> >>>>  }
> >>>>  
> >>>>
> >>>
> >>> Hmm, why not let the kdump module depend on drm?
> >>
> >> If you do not like it we can consider add it to kdump module..
> > 
> > So now if I build initrd w/o plymouth, I will not have frame buffer
> > console in initrd. That looks more like a general issue to me.
> > 
> > WANG Chao
> 
> Do we really need a fb console?
> If there is a valid reason, I will change "return 255" to "return 0".

Actually I don't have strong technical reason.

But from a user's perspective, there are some benefits:
- Higher resolution on the screen. It's good-looking and show me much
  more text.
- Initializing drm drivers would cause a flash on the screen and clear
  all existing text. I'd like this flash happens in initrd not later in
  real root.
  (During bootup, I care more about the status of real root systemd
  services than what's going on in initrd as long as it
  switches to root successfully)

I know it's weird for a normal boot to try to avoid plymouth but still want fb
console. So I wouldn't blame it if you don't feel comfortable about the
change.

Thanks
WANG Chao

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[Harald Hoyer]

On 05/29/2013 12:41 PM, WANG Chao wrote:
>>
>> Do we really need a fb console?
>> If there is a valid reason, I will change "return 255" to "return 0".
> 
> Actually I don't have strong technical reason.
> 
> But from a user's perspective, there are some benefits:
> - Higher resolution on the screen. It's good-looking and show me much
>   more text.
> - Initializing drm drivers would cause a flash on the screen and clear
>   all existing text. I'd like this flash happens in initrd not later in
>   real root.
>   (During bootup, I care more about the status of real root systemd
>   services than what's going on in initrd as long as it
>   switches to root successfully)
> 
> I know it's weird for a normal boot to try to avoid plymouth but still want fb
> console. So I wouldn't blame it if you don't feel comfortable about the
> change.
> 
> Thanks
> WANG Chao
> 

Well, my reasons are size and speed for those who want a very minimal initramfs.
The initramfs should not do more than it has to, to get to the real rootfs.

If someone omits the dracut plymouth module manually, he can also add drm in the
same step, if he wants.

I might change my mind, when we move to wayland terminal consoles. :)

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[WANG Chao]

On 05/29/13 at 12:54pm, Harald Hoyer wrote:
> On 05/29/2013 12:41 PM, WANG Chao wrote:
> >>
> >> Do we really need a fb console?
> >> If there is a valid reason, I will change "return 255" to "return 0".
> > 
> > Actually I don't have strong technical reason.
> > 
> > But from a user's perspective, there are some benefits:
> > - Higher resolution on the screen. It's good-looking and show me much
> >   more text.
> > - Initializing drm drivers would cause a flash on the screen and clear
> >   all existing text. I'd like this flash happens in initrd not later in
> >   real root.
> >   (During bootup, I care more about the status of real root systemd
> >   services than what's going on in initrd as long as it
> >   switches to root successfully)
> > 
> > I know it's weird for a normal boot to try to avoid plymouth but still want fb
> > console. So I wouldn't blame it if you don't feel comfortable about the
> > change.
> > 
> > Thanks
> > WANG Chao
> > 
> 
> Well, my reasons are size and speed for those who want a very minimal initramfs.
> The initramfs should not do more than it has to, to get to the real rootfs.
> 
> If someone omits the dracut plymouth module manually, he can also add drm in the
> same step, if he wants.
> 
> I might change my mind, when we move to wayland terminal consoles. :)

Point taken. kdump will pull in drm module.

Thanks!

Re: [PATCH] 50drm: Install dracut 50drm module in hostonly mode when drm driver is currently in use.

[Harald Hoyer]

On 05/29/2013 04:45 AM, Dave Young wrote:
> On 05/28/2013 08:09 PM, Harald Hoyer wrote:
>> On 05/24/2013 10:22 AM, WANG Chao wrote:
>>> Now only 50plymouth module can pull in 50drm and that's very limited.
>>> Because KMS capable drm drivers are much needed in initrd to have a
>>> frame buffer console on the screen.
>>>
>>> Particularly, when building kdump initrd, plymouth module is omitted,
>>> but drm is necessary to setup a working screen for one sitting in front
>>> of a monitor.
>>>
>>> Signed-off-by: WANG Chao <chaowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>> ---
>>>  modules.d/50drm/module-setup.sh | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>>
>>> diff --git a/modules.d/50drm/module-setup.sh b/modules.d/50drm/module-setup.sh
>>> index bf33c5b..648e8f4 100644
>>> --- a/modules.d/50drm/module-setup.sh
>>> +++ b/modules.d/50drm/module-setup.sh
>>> @@ -3,6 +3,10 @@
>>>  # ex: ts=8 sw=4 sts=4 et filetype=sh
>>>  
>>>  check() {
>>> +    if [[ $hostonly ]] && [ -d /sys/module/drm/drivers ]; then
>>> +        return 0
>>> +    fi
>>> +
>>>      return 255
>>>  }
>>>  
>>>
>>
>> Hmm, why not let the kdump module depend on drm?
> 
> If you do not like it we can consider add it to kdump module..
> 
>>
>> depends() {
>>     echo drm
>> }
>>
>> Anyway, do we really need drm for a simple console? Those drivers are really
>> really big and take a long time to load and initialize?
> 
> It's a little awkward, after kernel crashing suppose 1st kernel is in
> kms mode, it can not reset to nomodeset, so screen will keep black.
> 
> There's no such issue in normal initramfs because bios always reset
> devices for us.
> 

Ah! Thanks for the clarification! That makes sense. Because this happens only
for kexec, I suggest to add the dependency to the kdump module.