On Wed 14 Mar 13:05 PDT 2018, Christ, Austin wrote: > This patch is designed to address a possible issue where an interrupt is > fired but not yet handled by the i2c-qup driver and the kernel goes down as > kexec prepares to start a secondary kernel. In this case it is possible the > interrupt will be left unhandled. > What's the problem with not handling this IRQ? Does the hardware end up in some funky state? Are you worried that the kexec kernel will not function because there's a pending I2C interrupt? > This is not unique to the i2c-qup driver, similar patches have gone into > other drivers such as the following for the arm-smmu-v3 driver. > The only similarity I can see here is that the SMMU is shut down in order for any ongoing memory transaction to stop, which could be analog to ongoing BAM operations in the QUP driver. But in that case I think the shutdown should go in the BAM, to stop any ongoing transactions. Regards, Bjorn > commit 7aa8619a66aea52b145e04cbab4f8d6a4e5f3f3b > Author: Nate Watterson <nwatters@xxxxxxxxxxxxxx> > Date: Thu Jun 29 18:18:15 2017 -0400 > > iommu/arm-smmu-v3: Implement shutdown method > > The shutdown method disables the SMMU to avoid corrupting a new kernel > started with kexec. > > Signed-off-by: Nate Watterson <nwatters@xxxxxxxxxxxxxx> > Signed-off-by: Will Deacon <will.deacon@xxxxxxx> > > > > On 2/2/2018 4:36 PM, Bjorn Andersson wrote: > > On Tue 16 Jan 13:35 PST 2018, Austin Christ wrote: > > > > > This shutdown method disables I2C to avoid corrupting a new kernel > > > started with kexec. > > > > > > > Can you elaborate on the issue you're seeing here? In what way is the > > i2c-qup driver special, will there be similar patches for all other > > drivers in the system? > > > > Regards, > > Bjorn > > > > -- > Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, > Inc. > Qualcomm Technologies, Inc. is a member of the > Code Aurora Forum, a Linux Foundation Collaborative Project.
