Mediatek Driver 2023 -

0001-mtk-sleepctl-fix-pm_qos-stale-vote.patch

At 6:00 AM, she checked the battery graph: . Fixed. Part V: The Gray Zone The fix worked. But it was a “proprietary modification” to MediaTek’s binary-licensed driver—technically a violation of their software agreement.

A long silence. Then Chen sighed. “The fix was in our internal branch. It did not make the 2023 release. Management cut the schedule.”

/* original suspend logic continues... */ } mediatek driver 2023

static void mtk_sleepctl_suspend(struct device *dev) { struct mtk_sleepctl *ctl = dev_get_drvdata(dev); /* 2023-10-12: Force clear PM_QoS vote on suspend */ if (ctl->qos_active) { pm_qos_update_request(&ctl->qos_req, PM_QOS_DEFAULT_VALUE); ctl->qos_active = false; dev_info(dev, "Cleared stale QoS vote (MTK-DISP-2023 fix)\n"); }

Every time the phone went to sleep, the driver voted for maximum DDR frequency . And because the vote was never cleared, the memory controller ran at full speed all night.

For two weeks, the team blamed the battery vendor. For another week, they blamed the Android 14 beta. But Lena knew the truth: the kernel was lying to them. 0001-mtk-sleepctl-fix-pm_qos-stale-vote

“You cannot change this now,” Chen said, sipping tea. “The driver is certified. Changing PM_QoS requires re-validation of the entire power management framework. That’s six weeks.”

“Your driver is melting batteries,” Lena replied.

She traced the logic. The mtk_sleepctl driver was supposed to suspend the display pipeline when the screen turned off. But in the 2023 revision, a junior engineer had added a “performance boost” for the new GPU: a function called mtk_disp_qos_boost() that never released its power-management Quality of Service (PM_QoS) vote. But it was a “proprietary modification” to MediaTek’s

Lena wrote a careful email to her CTO: “We can ship this patch as a ‘vendor enhancement.’ MediaTek does not need to know. But if they ever audit us, we lose support.” The CTO, a pragmatic woman named Priya, called her back in 30 seconds.

“If I disable it, the display won’t suspend at all. The phone will die in four hours.”

The header ends with:

“Ship it. I’ll handle MediaTek’s legal noise. And Lena—put a big comment in the code. If any engineer touches this in 2024 without reading your note, they’ll undo the fix.” The phone launched in November 2023. Reviewers praised its “all-day battery life.” No one knew about the zombie driver. No one thanked Lena.

She compiled the kernel. Flashed it to a test device. Let it sit overnight.