> -----Original Message----- > From: platform-driver-x86-owner@xxxxxxxxxxxxxxx <platform-driver-x86- > owner@xxxxxxxxxxxxxxx> On Behalf Of Pali Rohár > Sent: Wednesday, June 10, 2020 4:45 AM > To: Limonciello, Mario > Cc: rdunlap@xxxxxxxxxxxxx; y.linux@xxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx; > mjg59@xxxxxxxxxxxxx > Subject: Re: [PATCH v2 3/3] platform/x86: dell-wmi: add new dmi keys to > bios_to_linux_keycode > > > [EXTERNAL EMAIL] > > On Tuesday 09 June 2020 19:49:18 Mario.Limonciello@xxxxxxxx wrote: > > > > > > Looking at the last two lines... and for me it looks like that 0x00FF > > > and 0xFFFF are just "placeholders" or special values for unknown / > > > custom / unsupported / reserved / special / ... codes. > > > > > > It is really suspicious why first 38 values are defined, then there is > > > gap, then one value 255 and then huge gap to 65535. > > > > > > Mario, this looks like some mapping table between internal Dell BIOS > key > > > code and standard Linux key code. Are you able to get access to some > > > documentation which contains explanation of those Dell key numbers? > > > It could really help us to understand these gaps and what is correct > > > interpretation of these numbers. > > > > > > > The codes are actually 4 bytes in the table, but in practice nothing > above the > > first two bytes is used. > > > > Those two called out are special though, here are their meanings: > > > > 0x00FF is user programmable function > > 0xFFFF is no function > > > > For the purpose of memory consumption I think it's reasonable to ignore > the > > upper 2 bytes and special case these two. > > Thank you for information! > > So 0x00FF is "user programmable" button. Do I understand it correctly > that Dell/BIOS does not explicitly provide meaning for these buttons, > they do not have fixed functionality and therefore user should configure > them as he want? Correct > > And what does mean "no function"? I do not know what should I imagine if > I receive key press marked as "no function". It means no action is expected to occur, should behave like a no-op. I think discarding it makes fine sense. > > > > E.g. I remember that pressing Fn+Q or Fn+W on some Dell Latitude > > > generates code 255, which could prove my thesis about "special codes" > > > (which are probably not found in e.g. Windows or Linux mapping tables). > > > > > > > > }; > > > > > > > > > > /* > > > > > @@ -503,10 +504,7 @@ static void handle_dmi_entry(const struct > > > dmi_header *dm, void *opaque) > > > > > &table->keymap[i]; > > > > > > > > > > /* Uninitialized entries are 0 aka KEY_RESERVED. */ > > > > > - u16 keycode = (bios_entry->keycode < > > > > > - ARRAY_SIZE(bios_to_linux_keycode)) ? > > > > > - bios_to_linux_keycode[bios_entry->keycode] : > > > > > - KEY_RESERVED; > > > > > + u16 keycode = bios_to_linux_keycode[bios_entry->keycode]; > > > > > > > > > > /* > > > > > * Log if we find an entry in the DMI table that we don't > > > > > > > > > > > > > Something like: > > > > > > > > u16 keycode; > > > > > > > > keycode = bios_entry->keycode == 0xffff ? KEY_UNKNOWN : > > > > (bios_entry->keycode < > > > > ARRAY_SIZE(bios_to_linux_keycode)) ? > > > > bios_to_linux_keycode[bios_entry->keycode] : > > > > KEY_RESERVED; > > > > > > > > > > > > > > > > Also please fix this: > > > > (no To-header on input) <> > > > > > > Hint: specifying git send-email with '--to' argument instead of '--cc' > > > should help. > > > > > > > > > > > -- > > > > ~Randy > > > >
