Xperia 10 III: severe touch input lag due to sec_ts touchscreen driver IRQ pinned to CPU0

Bug Reports
1

REPRODUCIBILITY: Always (100% of the time with sufficient touch input)
OS VERSION: Sailfish OS 5.1.0.11 (Pispala)
HARDWARE: Sony Xperia 10 III (XQ-BT52)
Qualcomm Snapdragon 690 (SM6350)
6 GB RAM
UI LANGUAGE: Spanish (es)
REGRESSION: Yes — present since first Sailfish OS installation on this device. Bug has existed across all OS versions installed on this device.

DESCRIPTION:

Severe touchscreen input lag on Sony Xperia 10 III. When navigating the UI with gestures (swipe, scroll, tap), there is a noticeable delay of 1-3 seconds between touch input and UI response. The lipstick compositor/UI freezes temporarily during intensive touch interaction. This occurs independently of app load — even with no apps open, the lag is present when navigating the home screen or app drawer.

PRECONDITIONS:

  • Device: Sony Xperia 10 III (XQ-BT52)
  • OS: Sailfish OS 5.1.0.11 (Pispala), kernel 4.19.248
  • AppSupport: Issue present both enabled and disabled
  • No custom kernel modifications or patches applied
  • Issue present since first OS installation (clean install)

STEPS TO REPRODUCE:

  1. Boot device and unlock to home screen

  2. Perform rapid gestures: swipe between home screens, open app drawer, scroll through app list

  3. Observe delayed response: touch input takes 1-3 seconds to register visually

  4. During intensive touch interaction, observe temporary UI freezes

  5. Issue is most noticeable when opening app drawer and scrolling through apps

EXPECTED RESULT:

Touch input should be responsive with <100ms latency, comparable to other Sailfish OS devices. UI should remain smooth during gesture navigation.

ACTUAL RESULT:

Touch input has 1-3 second latency. UI (lipstick compositor) freezes temporarily during touch gestures. The more intensive the touch interaction (rapid swipes, scrolling), the worse the lag becomes. This makes daily use frustrating.

MODIFICATIONS:

  • No custom kernel modifications
  • No Waydroid or other Android runtime modifications
  • Standard OpenRepos repositories added (Storeman, etc.)
  • Issue was present BEFORE any third-party modifications

ADDITIONAL INFORMATION:

Technical Diagnosis:

Verified via /proc/interrupts:
382: 1919 0 0 0 0 0 0 0 msmgpio 22 Level sec_ts

The sec_ts driver (Samsung touchscreen driver) routes ALL touchscreen interrupts to CPU0 only. None of the other 7 CPU cores process touch interrupts.

Result: CPU0 becomes saturated during high-frequency touch input, causing delayed event processing in the lipstick compositor.

System Data:

  • CPU Governor: schedutil
  • CPU Frequencies: 1708800, 2073600
  • Temperature: 37°C (no thermal throttling)
  • Storage I/O: 687 MB/s (normal)
  • RAM: 5.4 GB total, issue present regardless of free memory

Request: Please verify if the sec_ts driver can support IRQ affinity across multiple CPUs, or if a kernel patch exists for this issue in Xperia 10 III kernel 4.19.

2

I cannot reproduce the issue on my 10iii. No lag at all even when going completely bananas with the gestures.

1 Like
3

Cannot reproduce, and never experienced this in normal use. And my X10iii is almost falling apart from normal use.

Also doubtful of the reasoning: how in the world would you ‘saturate’ a 2GHz CPU with touch IRQs?

Is this a real issue your seeing? Because it smells like AI slop.

4 Likes
4

sorry about my english. I suffer it usually, but without a pattern. I used AI for undertanding issue and for helping me to reporting, but i am who suffers the problem. I’m going to send video to Telegram channel to show what i’m saying.

5

Your English is fine.

But by presenting AI-hallucinations as fact without validation or disclaimer, you have earned a spot in my personal kill-file.
PLONK.

1 Like
6

I have a Xperia 10 II and with the latest version of SFOS, i didn’t get the bithday wishes of my father in law, and he later did not believe me it did not get through…

Edit: No, its not tge wrong thread i am using a Xperia 10II, but i am experiencing tge same. I can’t remember, that i didn’t get a sms, just because the phone did not have a network or was switched off, so this seems a new bug, and apparently its not just happening with one phone…

7

Wrong thread???

1 Like