[opensuse-kernel] Modularize PS/2 driver for Xen/EC2

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Davy Kager

23 Apr 2014 23 Apr '14

19:13

Hi, I've been using openSUSE as my private-server-distro of choice for a few years now (so apologies in advance for being blissfully ignorant of the inner workings of these systems). Since it's a Xen guest I'm using Kernel:stable/kernel-xen. Before that I used the kernel tied to the current openSUSE release. So far so good. BUT, on boot I'd always see the I8042 driver taking some time to detect hardware, only to throw an error telling me it couldn't: [ 1.268512] i8042: No controller found This makes sense, I'm running headless. There didn't seem to be a readily available solution to this problem, so I let it be. Now it turns out that folks at Arch Linux got annoyed by the same thing and pushed a few patches to upstream[0]. The final realization was with kernel 3.13[1]. Would it be possible to do the same in openSUSE? In particular: CONFIG_SERIO=m CONFIG_SERIO_I8042=m CONFIG_SERIO_LIBPS2=m # not entirely sure about this one CONFIG_INPUT_MOUSEDEV=m As far as I can tell this should be reasonably safe on Xen, even safer on kernel-ec2. It might also be time to do this for the -default and -desktop kernels. I don't have nearly enough experience with Linux to know the exact impact that would have. Would be nice to bypass this step during boot on boxes `in the cloud', though. Thanks! [0]: https://bugs.archlinux.org/task/27555#comment116488 [1]: https://www.archlinux.org/news/linux-313-warning-ps2-keyboard-support-is-now... -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

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Jeff Mahoney

23 Apr 23 Apr

19:26

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 4/23/14, 3:13 PM, Davy Kager wrote:

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Hi,

I've been using openSUSE as my private-server-distro of choice for a few years now (so apologies in advance for being blissfully ignorant of the inner workings of these systems). Since it's a Xen guest I'm using Kernel:stable/kernel-xen. Before that I used the kernel tied to the current openSUSE release. So far so good. BUT, on boot I'd always see the I8042 driver taking some time to detect hardware, only to throw an error telling me it couldn't: [ 1.268512] i8042: No controller found This makes sense, I'm running headless. There didn't seem to be a readily available solution to this problem, so I let it be.

Now it turns out that folks at Arch Linux got annoyed by the same thing and pushed a few patches to upstream[0]. The final realization was with kernel 3.13[1]. Would it be possible to do the same in openSUSE? In particular: CONFIG_SERIO=m CONFIG_SERIO_I8042=m CONFIG_SERIO_LIBPS2=m # not entirely sure about this one CONFIG_INPUT_MOUSEDEV=m

As far as I can tell this should be reasonably safe on Xen, even safer on kernel-ec2. It might also be time to do this for the -default and -desktop kernels. I don't have nearly enough experience with Linux to know the exact impact that would have. Would be nice to bypass this step during boot on boxes `in the cloud', though.

Wouldn't this mean that kernel-xen used as Dom0 would run into problems if the initrd failed? - -Jeff

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Thanks!

[0]: https://bugs.archlinux.org/task/27555#comment116488 [1]: https://www.archlinux.org/news/linux-313-warning-ps2-keyboard-support-is-now...

- -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) iQIcBAEBAgAGBQJTWBP7AAoJEB57S2MheeWyjUEP/2fVywLRVktYI+NSQ0cqOElU ZAKtOkK1n6z4xXI5MJphq+Gz43HKtPQ0ffGLn1ZMJVNnl4lQqney9rqoOCAV23/1 B4R274GLR6q1q9gLARyefYhDauTVfqVUQa/kSm94PHI+xGfgzlk5vSyY3VEXN/wR 4UeCy3BZPtRpcrV3lJxjXXbEiTJdGFwqvKzBzA+c5CsrggSFdgpeKxgKnZnUPrWP td6MBX+AQW0+mINZL+jXQl9h5pW9bWVUwQH2ZyLQrkFaKwwDbkBG6ZIyC7YCE0nI 2FdSgR7decH2UPkri19hUxDyr6L1CL0GkHuRt57HkJYEBQtzCFwXq6af9SB1ms1f laWfeKIoTOMVEfC5AM4Lr3wsI8O1o2A8fjO5/c38uY/lp2BUd2mzKTknL3JV3fwK WKdQVGYF4VbtupiZKmUlafAy74eEUu4BQXg5217JJYkorWrvaLgMyMrSOG3mMcyL m+L61zhxlnF7RV0wI2kLUf8gAn7rIOGQRjelPI2N+cSAcqDhSUCToWOqyc5o2q+o KreofEYEvTamzRYUpGls8eY4/HPe/WcVuOZDEYxUK5KDa6qBjAMMq4gt7Eg6LXm5 WabDz/md7ORTdU3d4SL6TxJ84SMim5PjkphuRpv+yvzrw/QAkvWzoe4GPgYoQGoN fCTMXC3RNSWV7aEHO8eN =MGL2 -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

Davy Kager

19:48

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-----Original Message----- From: Jeff Mahoney [mailto:jeffm@suse.com] Sent: Wednesday, April 23, 2014 21:27 To: opensuse-kernel@opensuse.org Subject: Re: [opensuse-kernel] Modularize PS/2 driver for Xen/EC2

Wouldn't this mean that kernel-xen used as Dom0 would run into problems if the initrd failed?

- -Jeff

Sorry, this isn't the ideal system for mailing list correspondence... Anyway, that's what I wasn't sure about. I'd imagine you can have the appropriate modules auto-loaded if you indeed still had PS/2 hardware. Not sure how that relates to early-boot scenarios as I've never had a need (nor the opportunity) to experience all this first-hand. The crux of the matter is probably whether or not PS/2 devices (attached to Xen Dom0) are still widespread enough to keep I8042 in its current state. How does kernel-ec2 compare to kernel-xen on the guest-side of things? The EC2 kernel is a lot sleeker, but I feel weird running it on a non-EC2 provider. A kernel-xen just for guests would be great. ;) Davy -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

Jan Beulich

24 Apr 24 Apr

07:05

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On 23.04.14 at 21:48, wrote: -----Original Message----- From: Jeff Mahoney [mailto:jeffm@suse.com] Sent: Wednesday, April 23, 2014 21:27 To: opensuse-kernel@opensuse.org Subject: Re: [opensuse-kernel] Modularize PS/2 driver for Xen/EC2

Wouldn't this mean that kernel-xen used as Dom0 would run into problems if the initrd failed?

Sorry, this isn't the ideal system for mailing list correspondence... Anyway, that's what I wasn't sure about. I'd imagine you can have the appropriate modules auto-loaded if you indeed still had PS/2 hardware. Not sure how that relates to early-boot scenarios as I've never had a need (nor the opportunity) to experience all this first-hand. The crux of the matter is probably whether or not PS/2 devices (attached to Xen Dom0) are still widespread enough to keep I8042 in its current state.

For kernel-xen that would be an option only if the other configs, namely -default, also did such a move. And I agree with Jeff that this would bear some risks, and hence is better avoided at this point. For -ec2, otoh, these should be disabled altogether now that this is possible (when these configs got branched off, the option wasn't user-selectable yet, and one of the weaknesses of the kernel configuration mechanism is that you don't get notified during "make oldconfig" when an already set option becomes user selectable, i.e. I simply didn't notice the opportunity to get rid of these).

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How does kernel-ec2 compare to kernel-xen on the guest-side of things? The EC2 kernel is a lot sleeker, but I feel weird running it on a non-EC2 provider. A kernel-xen just for guests would be great. ;)

There's nothing EC2-specific in them, they solely exist because of the compatibility need with much older hypervisors. Since Amazon confirmed that on those old hypervisors no device pass-through would ever be done, we took the opportunity of having this separate config to (try to) strip off all drivers for "real" hardware devices. Hence for a DomU without device pass-through, this flavor should be quite fine even outside of EC2. But (I hope you understood this already) the flavor is _not_ suitable for use in Dom0 (along with "real" hardware driver support, the capability to run in the privileged Dom0 mode got disabled too, as also guaranteed to never be needed in EC2 instances). Jan -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

Davy Kager

08:27

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-----Original Message----- From: Jan Beulich [mailto:JBeulich@suse.com] Sent: Thursday, April 24, 2014 09:06 To: Davy Kager Cc: opensuse-kernel@opensuse.org; Jeff Mahoney Subject: RE: [opensuse-kernel] Modularize PS/2 driver for Xen/EC2

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On 23.04.14 at 21:48, wrote: How does kernel-ec2 compare to kernel-xen on the guest-side of things? The EC2 kernel is a lot sleeker, but I feel weird running it on a non-EC2 provider. A kernel-xen just for guests would be great. ;)

There's nothing EC2-specific in them, they solely exist because of the compatibility need with much older hypervisors. Since Amazon confirmed that on those old hypervisors no device pass-through would ever be done, we took the opportunity of having this separate config to (try to) strip off all drivers for "real" hardware devices. Hence for a DomU without device pass- through, this flavor should be quite fine even outside of EC2. But (I hope you understood this already) the flavor is _not_ suitable for use in Dom0 (along with "real" hardware driver support, the capability to run in the privileged Dom0 mode got disabled too, as also guaranteed to never be needed in EC2 instances).

Jan

Thanks for all the information! My openSUSE installation is running on Linode, which seems very similar to EC2. Should be all virtual kit, kernel is loaded through pv-grub. Only thing that might be "real" is the CPU (because of warnings below). My reasons for choosing kernel-xen are that a) It "finds" more RAM than vanilla. b) It runs smoothly without further tweaking. c) It gives me proper timestamps in dmesg. I just installed kernel-ec2-3.14.1-24 to see how it would do. There are some warnings on mkinitrd: modprobe: FATAL: Module thermal not found. WARNING: no dependencies for kernel module 'thermal' found. modprobe: FATAL: Module processor not found. WARNING: no dependencies for kernel module 'processor' found. modprobe: FATAL: Module fan not found. WARNING: no dependencies for kernel module 'fan' found. Are these predefined somewhere? My virtual box definitely doesn't have access to the system's thermals. ;) Upon reboot I get the expected dmesg output related to this thread: [ 1.204265] i8042: No controller found [ 1.204394] mousedev: PS/2 mouse device common for all mice My observations so far: * kernel-ec2 is doing very well inspite of the warnings mentioned above. * `free' shows me about 1 MiB less RAM than kernel-xen did. * HUGE space saver! From 175 MB to 40 MB. I'm liking it. * Seems to boot just like kernel-xen. Are (all) Xen DomU-specific patches in this kernel? As I wrote kernel-xen was one of the reasons for me to stick with SUSE. If possible I'd like to stick with kernel-ec2, especially if the PS/2 bits are taken out, and assuming I don't lose any of the Xen hotness that the mighty big kernel-xen brings. It's a much more economic solution space-wise. Thanks, Davy -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

Jan Beulich

08:35

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On 24.04.14 at 10:27, wrote: I just installed kernel-ec2-3.14.1-24 to see how it would do. There are some warnings on mkinitrd: modprobe: FATAL: Module thermal not found. WARNING: no dependencies for kernel module 'thermal' found. modprobe: FATAL: Module processor not found. WARNING: no dependencies for kernel module 'processor' found. modprobe: FATAL: Module fan not found. WARNING: no dependencies for kernel module 'fan' found. Are these predefined somewhere? My virtual box definitely doesn't have access to the system's thermals. ;)

No, that's a shortcoming of how the initrd gets set up - these drivers shouldn't even be attempted to be included in a PV DomU. But since this is only cosmetic, I guess no-one cared enough so far to suppress these warnings.

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* Seems to boot just like kernel-xen. Are (all) Xen DomU-specific patches in this kernel?

Yes, the sources the various flavors get built from are the same. Jan -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

Davy Kager

08:51

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-----Original Message----- From: Jan Beulich [mailto:JBeulich@suse.com] Sent: Thursday, April 24, 2014 10:35 To: Davy Kager Cc: opensuse-kernel@opensuse.org; Jeff Mahoney Subject: RE: [opensuse-kernel] Modularize PS/2 driver for Xen/EC2

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On 24.04.14 at 10:27, wrote: I just installed kernel-ec2-3.14.1-24 to see how it would do. There are some warnings on mkinitrd: modprobe: FATAL: Module thermal not found. WARNING: no dependencies for kernel module 'thermal' found. modprobe: FATAL: Module processor not found. WARNING: no dependencies for kernel module 'processor' found. modprobe: FATAL: Module fan not found. WARNING: no dependencies for kernel module 'fan' found. Are these predefined somewhere? My virtual box definitely doesn't have access to the system's thermals. ;)

No, that's a shortcoming of how the initrd gets set up - these drivers shouldn't even be attempted to be included in a PV DomU. But since this is only cosmetic, I guess no-one cared enough so far to suppress these warnings.

AKA safe to ignore? Good to know, thanks! Thought this might be configurable in /etc/sysconfig/kernel. Either way, system appears to run fine.

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* Seems to boot just like kernel-xen. Are (all) Xen DomU-specific patches in this kernel?

Yes, the sources the various flavors get built from are the same.

Jan

Okay, and this also goes for SUSE patches and Xen-optimized kernel configuration changes? That is, kernel-ec2 is like kernel-xen minus the hypervisor/Dom0 side of things, and minus real hardware drivers? And I'm not doing something silly running this on a relatively modern Xen PV system? Would be great if the SERIO/I8042/LIBPS2/MOUSEDEV bits can be taken care of for kernel-ec2. I appreciate that doing this for all kernels would be a risk that isn't worth taking if the only real advantage is that some people save 1 second on their boot process while others are left with broken hardware. Thanks for all the helpful replies! Davy -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

Jan Beulich

08:58

>>> On 24.04.14 at 10:51,  wrote:
>> From: Jan Beulich [mailto:JBeulich@suse.com]
>> >>> On 24.04.14 at 10:27,  wrote:
>> > *  Seems to boot just like kernel-xen.  Are (all) Xen DomU-specific
>> > patches in this kernel?
>> 
>> Yes, the sources the various flavors get built from are the same.
> 
> Okay, and this also goes for SUSE patches and Xen-optimized kernel 
> configuration changes?  That is, kernel-ec2 is like kernel-xen minus the 
> hypervisor/Dom0 side of things, and minus real hardware drivers?  And I'm not 
> doing something silly running this on a relatively modern Xen PV system?

Yes, yes, and yes.

> Would be great if the SERIO/I8042/LIBPS2/MOUSEDEV bits can be taken care of 
> for kernel-ec2.  I appreciate that doing this for all kernels would be a risk 
> that isn't worth taking if the only real advantage is that some people save 1 
> second on their boot process while others are left with broken hardware.

Will be done (already queued locally), but not immediately (likely only
with the first 3.15-rc Xen merge).

Jan

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Olaf Hering

10:30

On Wed, Apr 23, Davy Kager wrote:

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[ 1.268512] i8042: No controller found

This has to be fixed in upstream kernel. There is no need to bother anyone with this message. It should be printed with debug level instead of the priority it has now. Olaf -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org

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Davy Kager
Jan Beulich
Jeff Mahoney
Olaf Hering