Commit d579478c authored by Sasha Finkelstein's avatar Sasha Finkelstein Committed by Dmitry Torokhov
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Input: apple_z2 - fix reading incorrect reports after exiting sleep 



Under certain conditions (more prevalent after a suspend/resume cycle),
the touchscreen controller can send the "boot complete" interrupt before
it actually finished booting. In those cases, attempting to read touch
data resuls in a stream of "not ready" messages being read and
interpreted as a touch report. Check that the response is in fact a
touch report and discard it otherwise.

Reported-by: default avatarpitust <piotr@stelmaszek.com>
Closes: https://oftc.catirclogs.org/asahi/2025-12-17#34878715;


Fixes: 471a92f8 ("Input: apple_z2 - add a driver for Apple Z2 touchscreens")
Signed-off-by: default avatarSasha Finkelstein <fnkl.kernel@gmail.com>
Link: https://patch.msgid.link/20251218-z2-init-fix-v1-1-48e3aa239caf@gmail.com


Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent bf40644e

drivers/input/touchscreen/apple_z2.c

+4 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#define APPLE_Z2_TOUCH_STARTED           3

#define APPLE_Z2_TOUCH_MOVED             4

#define APPLE_Z2_CMD_READ_INTERRUPT_DATA 0xEB

#define APPLE_Z2_REPLY_INTERRUPT_DATA    0xE1

#define APPLE_Z2_HBPP_CMD_BLOB           0x3001

#define APPLE_Z2_FW_MAGIC                0x5746325A

#define LOAD_COMMAND_INIT_PAYLOAD        0
@@ -142,6 +143,9 @@ static int apple_z2_read_packet(struct apple_z2 *z2) 
	if (error)

		return error;



	if (z2->rx_buf[0] != APPLE_Z2_REPLY_INTERRUPT_DATA)

		return 0;



	pkt_len = (get_unaligned_le16(z2->rx_buf + 1) + 8) & 0xfffffffc;



	error = spi_read(z2->spidev, z2->rx_buf, pkt_len);