Messages in this thread | | | Subject | Re: [RFC] tty/sysrq: Add alternative SysRq key | From | Andrzej Pietrasiewicz <> | Date | Mon, 15 Nov 2021 15:48:59 +0100 |
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Jiri, Greg,
W dniu 05.11.2021 o 15:06, Andrzej Pietrasiewicz pisze: > Hi Greg, > > W dniu 05.11.2021 o 14:27, Greg Kroah-Hartman pisze: >> On Fri, Nov 05, 2021 at 02:01:23PM +0100, Andrzej Pietrasiewicz wrote: >>> Hi, >>> >>> W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze: >>>> Hi Maciej, >>>> >>>> W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze: >>>>> On Thu, 4 Nov 2021, Maciej W. Rozycki wrote: >>>>> >>>>>> The reason for this is with their more recent laptops Lenovo in their >>>>>> infinite wisdom have placed the <PrintScreen> key (which in a traditional >>>>>> PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their >>>>>> keyboards between the right <Alt> and <Ctrl> keys. With thumbs not being >>>>>> as accurate as other fingers (and the overall misdesign of the keyboard >>>>>> and touchpad interface) you can imagine how often I have inadvertently hit >>>>>> <SysRq> combined with a letter key, wreaking havoc to my system (and of >>>>>> course I want to keep the key enabled for times when I do need it). >>>>> >>>>> On second thoughts this can be disabled with `setkeycodes 54 0' once we >>>>> do have an alternative combination available. >>>>> >>>> >>>> Doesn't `setkeycodes` affect only one keyboard? What if there are more >>>> keyboards connected to a machine? >>>> >>>> From drivers/tty/vt/keyboard.c: >>>> >>>> /* >>>> * Translation of scancodes to keycodes. We set them on only the first >>>> * keyboard in the list that accepts the scancode and keycode. >>>> * Explanation for not choosing the first attached keyboard anymore: >>>> * USB keyboards for example have two event devices: one for all "normal" >>>> * keys and one for extra function keys (like "volume up", "make coffee", >>>> * etc.). So this means that scancodes for the extra function keys won't >>>> * be valid for the first event device, but will be for the second. >>>> */ >>>> >>> >>> My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq, >>> don't we lose F10? >> >> The fact that this patch adds a "new" sysrq key no matter what is a >> non-starter, please think through the consequences of such a change... >> > > I wouldn't say this RFC adds a "new" sysrq no matter what. It does so only > when the input device (keyboard) does _not_ have SysRq key at all. So I would > say that this patch adds a replacement SysRq key if the SysRq key proper is > _physically_ absent. Which seems not such a bad thing to me. The problem I'm > trying to solve is exactly this: what to use as SysRq if there's no SysRq? >
What approach is acceptable then? Any criteria other than "go guess"? Is "connect an external keyboard" the _only_ choice Linux wants to offer to its users in case of devices such as e.g. Chromebooks?
Regards,
Andrzej
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