On Fri, Jul 14, 2023 at 04:29:08PM +0200, Konrad Dybcio wrote:
On 14.07.2023 15:02, Johan Hovold wrote:
The operating-performance-point vote needs to be dropped when shutting down the port to avoid wasting power by keeping resources like power domains in an unnecessarily high performance state (e.g. when a UART connected Bluetooth controller is not in use).
Fixes: a5819b548af0 ("tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state") Cc: stable@vger.kernel.org # 5.9 Cc: Rajendra Nayak quic_rjendra@quicinc.com Cc: Matthias Kaehlcke mka@chromium.org Signed-off-by: Johan Hovold johan+linaro@kernel.org
I don't know a whole lot about this subsystem, but the PM call has a pointer to uport which already contains this clock rate.. Is it zeroed out by the core before we reach it, which would prevent us from reusing it?
No, but this driver has other issues and I couldn't be arsed fixing them before addressing this bug.
Specifically that uartclk variable can currently be set by userspace...
I'll fix that up next week.
Johan