linux-kernel - [PATCH v2 3/3] platform/x86: dell-wmi: add new dmi keys to bios_to_linux

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Date:   Mon,  8 Jun 2020 19:05:30 -0400
From:   Y Paritcher <y.linux@...itcher.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        Matthew Garrett <mjg59@...f.ucam.org>,
        Pali Rohár <pali@...nel.org>,
        Mario.Limonciello@...l.com
Subject: [PATCH v2 3/3] platform/x86: dell-wmi: add new dmi keys to bios_to_linux_keycode

Increase length of bios_to_linux_keycode to 2 bytes (the true size of a
keycode) to allow for a new keycode 0xffff, this silences the following
messages being logged at startup on a Dell Inspiron 5593:

    dell_wmi: firmware scancode 0x48 maps to unrecognized keycode 0xffff
    dell_wmi: firmware scancode 0x50 maps to unrecognized keycode 0xffff

as per this code comment:

   Log if we find an entry in the DMI table that we don't
   understand.  If this happens, we should figure out what
   the entry means and add it to bios_to_linux_keycode.

These are keycodes included in the 0xB2 DMI table, for which the
corosponding keys are not known.

Now when a user will encounter this key, a proper message wil be printed:

    dell_wmi: Unknown key with type 0xXXXX and code 0xXXXX pressed

This will then allow the key to be identified properly.

Signed-off-by: Y Paritcher <y.linux@...itcher.com>
---
 drivers/platform/x86/dell-wmi.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 6b510f8431a3..dae1db96b5a0 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -196,7 +196,7 @@ struct dell_dmi_results {
 };
 
 /* Uninitialized entries here are KEY_RESERVED == 0. */
-static const u16 bios_to_linux_keycode[256] = {
+static const u16 bios_to_linux_keycode[65536] = {
 	[0]	= KEY_MEDIA,
 	[1]	= KEY_NEXTSONG,
 	[2]	= KEY_PLAYPAUSE,
@@ -237,6 +237,7 @@ static const u16 bios_to_linux_keycode[256] = {
 	[37]	= KEY_UNKNOWN,
 	[38]	= KEY_MICMUTE,
 	[255]	= KEY_PROG3,
+	[65535]	= KEY_UNKNOWN,
 };
 
 /*
@@ -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
-- 
2.27.0