Messages in this thread | | | Subject | Re: [RFC] tty/sysrq: Add alternative SysRq key | From | Andrzej Pietrasiewicz <> | Date | Fri, 5 Nov 2021 15:06:23 +0100 |
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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?
Andrzej
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