From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Wed, 8 Feb 2017 11:23:47 +0000 Subject: [PATCH 1/2] clk: scpi: RfC - Allow to ignore invalid SCPI DVFS clock rates In-Reply-To: References: <3b60654a-88b6-6262-396e-a058ade1c586@gmail.com> Message-ID: <209248b8-2a1c-e00f-d8a8-b82759772b5d@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/02/17 21:03, Heiner Kallweit wrote: > Introduce an optional property "clock-max-frequency" for SCPI DVFS > clocks. All frequencies for the respective clock exceeding this > threshold will be ignored. > > This is useful on systems where the firmware offers too optimistic > clock rates causing instabilities and crashes. > It clearly means the firmware/hardware(IOW platform) was not tested correctly before firmware advertised the OPPs. It needs to fixed in the firmware. The approach should be advertise the known minimal set working rather than the set for which hardware was designed. That's the whole reason while these are kept in firmware so the OS need not worry about such details. So NACK, go fix the firmware or disable it completely and be happy with the boot frequency. -- Regards, Sudeep From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Wed, 8 Feb 2017 11:23:47 +0000 Subject: [PATCH 1/2] clk: scpi: RfC - Allow to ignore invalid SCPI DVFS clock rates In-Reply-To: References: <3b60654a-88b6-6262-396e-a058ade1c586@gmail.com> Message-ID: <209248b8-2a1c-e00f-d8a8-b82759772b5d@arm.com> To: linus-amlogic@lists.infradead.org List-Id: linus-amlogic.lists.infradead.org On 04/02/17 21:03, Heiner Kallweit wrote: > Introduce an optional property "clock-max-frequency" for SCPI DVFS > clocks. All frequencies for the respective clock exceeding this > threshold will be ignored. > > This is useful on systems where the firmware offers too optimistic > clock rates causing instabilities and crashes. > It clearly means the firmware/hardware(IOW platform) was not tested correctly before firmware advertised the OPPs. It needs to fixed in the firmware. The approach should be advertise the known minimal set working rather than the set for which hardware was designed. That's the whole reason while these are kept in firmware so the OS need not worry about such details. So NACK, go fix the firmware or disable it completely and be happy with the boot frequency. -- Regards, Sudeep