Hi, On 9/13/23 23:27, Stephen Boyd wrote: > I recently looked at some crash reports on ChromeOS devices that call > into this intel_scu_ipc driver. They were hitting timeouts, and it > certainly looks possible for those timeouts to be triggering because of > scheduling issues. Once things started going south, the timeouts kept > coming. Maybe that's because the other side got seriously confused? I > don't know. > > I added some sleeps to these paths to trigger the timeout behavior to > make sure the code works. Simply sleeping for a long time in busy_loop() > hits the timeout, which could happen if the system is scheduling lots of > other things at the time. > > I couldn't really test the last patch because forcing a timeout or > returning immediately wasn't fast enough to trigger the second > transaction to run into the first one being processed. Thank you for your patch, I've applied this patch to my fixes branch: https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=fixes Note it will show up in my fixes branch once I've pushed my local branch there, which might take a while. I will include this patch in my next fixes pull-req to Linus for the current kernel development cycle. Regards, Hans > Changes from v3 (https://lore.kernel.org/r/20230911193937.302552-1-swboyd@xxxxxxxxxxxx): > * Use readx_poll_timeout() to shorten a line > > Changes from v2 (https://lore.kernel.org/r/20230906180944.2197111-1-swboyd@xxxxxxxxxxxx): > * Use read_poll_timeout() helper in patch #1 (again) > * New patch #3 to fix bug pointed out by Andy > * Consolidate more code into busy check in patch #4 > > Changes from v1 (https://lore.kernel.org/r/20230831011405.3246849-1-swboyd@xxxxxxxxxxxx): > * Don't use read_poll_timeout() helper in patch 1, just add code > * Rewrite patch 2 to be simpler > * Make intel_scu_ipc_busy() return -EBUSY when busy > * Downgrade dev_err() to dev_dbg() in intel_scu_ipc_busy() > > Stephen Boyd (4): > platform/x86: intel_scu_ipc: Check status after timeout in busy_loop() > platform/x86: intel_scu_ipc: Check status upon timeout in > ipc_wait_for_interrupt() > platform/x86: intel_scu_ipc: Don't override scu in > intel_scu_ipc_dev_simple_command() > platform/x86: intel_scu_ipc: Fail IPC send if still busy > > drivers/platform/x86/intel_scu_ipc.c | 66 +++++++++++++++++----------- > 1 file changed, 40 insertions(+), 26 deletions(-) > > Cc: Prashant Malani <pmalani@xxxxxxxxxxxx> > > base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c
