[PATCH] HID: intel-ish-hid: Reset enum_devices_done before enumeration

[PATCH] HID: intel-ish-hid: Reset enum_devices_done before enumeration

[Zhang Lixu]

Some systems have enabled ISH without any sensors. In this case sending
HOSTIF_DM_ENUM_DEVICES results in 0 sensors. This triggers ISH hardware
reset on subsequent enumeration after S3/S4 resume.

The enum_devices_done flag was not reset before sending the
HOSTIF_DM_ENUM_DEVICES command. On subsequent enumeration calls (such as
after S3/S4 resume), this flag retains its previous true value, causing the
wait loop to be skipped and returning prematurely to hid_ishtp_cl_init().
If 0 HID devices are found, hid_ishtp_cl_init() skips getting HID device
descriptors and sets init_done to true. When the delayed enumeration
response arrives with init_done already true, the driver treats it as a bad
packet and triggers an ISH hardware reset.

Set enum_devices_done to false before sending the enumeration command,
consistent with similar functions like ishtp_get_hid_descriptor() and
ishtp_get_report_descriptor() which reset their respective flags.

Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/intel-ish-hid/ishtp-hid-client.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hid/intel-ish-hid/ishtp-hid-client.c b/drivers/hid/intel-ish-hid/ishtp-hid-client.c
index f37b3bc2bb7d..6d64008f2ce0 100644
--- a/drivers/hid/intel-ish-hid/ishtp-hid-client.c
+++ b/drivers/hid/intel-ish-hid/ishtp-hid-client.c
@@ -495,6 +495,7 @@ static int ishtp_enum_enum_devices(struct ishtp_cl *hid_ishtp_cl)
 	int rv;
 
 	/* Send HOSTIF_DM_ENUM_DEVICES */
+	client_data->enum_devices_done = false;
 	memset(&msg, 0, sizeof(struct hostif_msg));
 	msg.hdr.command = HOSTIF_DM_ENUM_DEVICES;
 	rv = ishtp_cl_send(hid_ishtp_cl, (unsigned char *)&msg,

base-commit: c75caf76ed86bbc15a72808f48f8df1608a0886c
-- 
2.43.0

Re: [PATCH] HID: intel-ish-hid: Reset enum_devices_done before enumeration

[Benjamin Tissoires]

On Fri, 12 Dec 2025 10:51:50 +0800, Zhang Lixu wrote:
> Some systems have enabled ISH without any sensors. In this case sending
> HOSTIF_DM_ENUM_DEVICES results in 0 sensors. This triggers ISH hardware
> reset on subsequent enumeration after S3/S4 resume.
> 
> The enum_devices_done flag was not reset before sending the
> HOSTIF_DM_ENUM_DEVICES command. On subsequent enumeration calls (such as
> after S3/S4 resume), this flag retains its previous true value, causing the
> wait loop to be skipped and returning prematurely to hid_ishtp_cl_init().
> If 0 HID devices are found, hid_ishtp_cl_init() skips getting HID device
> descriptors and sets init_done to true. When the delayed enumeration
> response arrives with init_done already true, the driver treats it as a bad
> packet and triggers an ISH hardware reset.
> 
> [...]

Applied to hid/hid.git (for-6.19/upstream-fixes), thanks!

[1/1] HID: intel-ish-hid: Reset enum_devices_done before enumeration
      https://git.kernel.org/hid/hid/c/56e230723e3a

Cheers,
-- 
Benjamin Tissoires <bentiss@kernel.org>