Bugfix for quantum/dip_switch.c

[mtei]

Description

qmk_firmware/quantum/dip_switch.c

Line 63 in 974f83e

memcpy(last_dip_switch_state, dip_switch_state, sizeof(&dip_switch_state));

The value of sizeof(&dip_switch_state) is always set to 2. It should be sizeof(dip_switch_state).

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[mtei]

@drashna , could you please confirm this PR?

[drashna]

Honestly, most of this code was copy-pasted from the planck custom matrix...

However, tested the change on my Planck rev6 and works as expected.

✅

[drashna]

And nice catch!

[mtei]

FYI:

This bug causes undesirable behavior when there are three or more dip switches (five or more in the case of ARM). The callback function is called on every scan, as shown in the following example.

*** Yushakobo - Helix Beta disconnected -- 0xFEED:0x3060
*** Yushakobo - Helix Beta connected -- 0xFEED:0x3060
  >  002001 : dump_pbuf 16
     000000 : keyboard_pre_init_user()
     000000 : dip_switch_update_user(0,1)
  >  000000 : dip_switch_update_user(1,1)
     000000 : dip_switch_update_user(2,1)
     000000 : dip_switch_update_user(3,1)
     000000 : dip_switch_update_mask_user(0b1111)
  >  000000 : keyboard_post_init_user()
     000001 : dip_switch_update_user(2,1)
     000001 : dip_switch_update_user(3,1)
     000001 : dip_switch_update_mask_user(0b1111)
     000001 : dip_switch_update_user(2,1)
     000001 : dip_switch_update_user(3,1)
     000001 : dip_switch_update_mask_user(0b1111)
     000002 : dip_switch_update_user(2,1)
     000002 : dip_switch_update_user(3,1)
     000002 : dip_switch_update_mask_user(0b1111)

[drashna]

I've seen reports of a slowed down matrix scanning since the code was moved into core. If it's calling the called on every scan, that definitely could be the cause of the issue.