Re: [PATCH v3 1/5] clk: Respect CLK_OPS_PARENT_ENABLE during recalc
From: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Date: 2026-01-27 18:18:43
Also in:
linux-clk, linux-mediatek, lkml
On Tuesday, 27 January 2026 18:25:04 Central European Standard Time Mark Brown wrote:
On Tue, Jan 27, 2026 at 05:01:35PM +0000, Mark Brown wrote:quoted
On Fri, Oct 10, 2025 at 10:47:09PM +0200, Nicolas Frattaroli wrote:quoted
When CLK_OPS_PARENT_ENABLE was introduced, it guarded various clock operations, such as setting the rate or switching parents. However, another operation that can and often does touch actual hardware state is recalc_rate, which may also be affected by such a dependency.I'm seeing boot regressions in -next on the Avenger96 which bisect to this patch in -next. The board resets during startup:I am also seeing some similar regressions even earlier on i.MX8MP platforms, though they're resetting even earlier before any output is produced (even with earlycon). Didn't confirm yet with a revert or anything though.
Someone else seemingly bisected to this commit on i.MX8MP as well and replied to the RESEND of the series, and confirmed with a revert[1]. I'm somewhat surprised by this, because to me it doesn't make intuitive sense that some platforms would rely on CLK_OPS_PARENT_ENABLE to not enable the parent clock during a recalc. Can someone let me know which clocks (with which parent) in those affected devices is causing this? I'm wondering if this change unmasked some undeclared dependency that it's now stumbling over because it's enabling the parent earlier than ever. Would appreciate if we could fix up the affected platforms rather than revert this, because the platform I added this for was definitely using a parent-child relationship, and definitely needed to have the parent clock on during recalc. I can always bring back the RPM model I went for previously, but that feels like more of a hack around this caveat than a proper description of the clock relationship. To not have me break everyone's -next for days on end, feel free to drop this patch. MT8196, which this was added for, doesn't boot with mainline yet anyway. Kind regards, Nicolas Frattaroli https://lore.kernel.org/all/6239343.lOV4Wx5bFT@steina-w/ (local) [1]