Mediatek Driver - 2023
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.
/* original suspend logic continues... */ }
The symptom was baffling. A flagship phone running the new Dimensity 9300 chip would lose 8% battery life overnight while in “deep sleep.” The logs showed nothing. No runaway apps. No wake locks. Just... death by a thousand invisible cuts.
She compiled the kernel. Flashed it to a test device. Let it sit overnight. mediatek driver 2023
0001-mtk-sleepctl-fix-pm_qos-stale-vote.patch
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 in the kernel source tree, deep inside drivers/misc/mediatek/conn_mgr/ , there remains a patch file named: Every time the phone went to sleep, the
“Your driver is melting batteries,” Lena replied.
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"); }
/* * Fixed: December 2023. * If you are reading this in 2025 and battery drain returns, * look for new PM_QoS votes. They multiply like rabbits. * - Lena Wei, last commit of the year. */ And somewhere in MediaTek’s Hsinchu office, Dr. Chen quietly merged Lena’s fix into the 2024 driver branch, pretending he had written it himself. Because in the world of chipset drivers, credit is fleeting—but a working phone is forever. */ } The symptom was baffling
A long silence. Then Chen sighed. “The fix was in our internal branch. It did not make the 2023 release. Management cut the schedule.”
“If I disable it, the display won’t suspend at all. The phone will die in four hours.”
“Then disable it in your device tree.”
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.
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