From 62373b7879ada744ea4fc6766b2fb55229eac11f Mon Sep 17 00:00:00 2001 From: Ekansh Gupta Date: Wed, 29 Jul 2026 10:43:48 +0100 Subject: [PATCH] misc: fastrpc: Expand context ID mask for DSP polling mode support Current FastRPC context uses a 12-bit mask: [ID(8 bits)][PD type(4 bits)] = GENMASK(11, 4) This works for normal calls but fails for DSP polling mode. Polling mode expects a 16-bit layout: [15:8] = context ID (8 bits) [7:5] = reserved [4] = async mode bit [3:0] = PD type (4 bits) If async bit (bit 4) is set, DSP disables polling. With current mask, odd IDs can set this bit, causing DSP to skip poll updates. Update FASTRPC_CTXID_MASK to GENMASK(15, 8) so IDs occupy upper byte and lower byte is left for DSP flags and PD type. Reserved bits remain unused. This change is compatible with polling mode and does not break non-polling behavior. Bit layout: [15:8] = CCCCCCCC (context ID) [7:5] = xxx (reserved) [4] = A (async mode) [3:0] = PPPP (PD type) Reviewed-by: Dmitry Baryshkov Signed-off-by: Ekansh Gupta Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260729094352.111065-7-srini@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/misc/fastrpc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 9d8dcd836a75..d42b3e9e2a07 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -39,7 +39,7 @@ #define FASTRPC_CTX_MAX (256) #define FASTRPC_INIT_HANDLE 1 #define FASTRPC_DSP_UTILITIES_HANDLE 2 -#define FASTRPC_CTXID_MASK GENMASK(11, 4) +#define FASTRPC_CTXID_MASK GENMASK(15, 8) #define INIT_FILELEN_MAX (2 * 1024 * 1024) #define INIT_FILE_NAMELEN_MAX (128) #define FASTRPC_DEVICE_NAME "fastrpc"