What happened
With two external displays connected, brightness changes in Crisp can occasionally take several seconds or tens of seconds to reach the monitor. When one display has a slow or unresponsive DDC/CI channel, brightness changes for the other healthy display are delayed as well.
The slider should respond immediately, and each external display should process DDC brightness changes independently so one failing channel cannot block another monitor.
Steps to reproduce
- Connect two AOC U32N10 external displays.
- Open Crisp and expand both external display controls.
- Adjust brightness repeatedly until one display enters the intermittent slow-DDC state.
- While that display is still processing the DDC request, adjust brightness on the other display.
- Observe that the second display can wait behind the first request instead of updating independently.
Crisp version
1.5.0
macOS version
macOS 26.5.1 (25F80)
Mac model and chip
MacBook Pro (Mac17,8), Apple M5 Pro
Monitor(s) and how they are connected
Two AOC U32N10 4K displays connected as separate external display links; one landscape and one rotated 90 degrees. macOS System Information does not report the cable or adapter transport for either display.
Anything else
A direct channel probe reproduced the difference clearly: one IOAVServiceReadI2C request failed after 12.131 seconds, while the other display completed the same operation in about 10 ms. Crisp used one global serial DDC queue, so the slow request blocked unrelated external-display brightness work.
A fix is proposed in PR #71.
What happened
With two external displays connected, brightness changes in Crisp can occasionally take several seconds or tens of seconds to reach the monitor. When one display has a slow or unresponsive DDC/CI channel, brightness changes for the other healthy display are delayed as well.
The slider should respond immediately, and each external display should process DDC brightness changes independently so one failing channel cannot block another monitor.
Steps to reproduce
Crisp version
1.5.0
macOS version
macOS 26.5.1 (25F80)
Mac model and chip
MacBook Pro (Mac17,8), Apple M5 Pro
Monitor(s) and how they are connected
Two AOC U32N10 4K displays connected as separate external display links; one landscape and one rotated 90 degrees. macOS System Information does not report the cable or adapter transport for either display.
Anything else
A direct channel probe reproduced the difference clearly: one IOAVServiceReadI2C request failed after 12.131 seconds, while the other display completed the same operation in about 10 ms. Crisp used one global serial DDC queue, so the slow request blocked unrelated external-display brightness work.
A fix is proposed in PR #71.