linux-kernel - [PATCH] media: dvb_ca_en50221: Fix a bug for detecting CI MODULE

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Message-Id: <20240308121021.1732-1-yongsuyoo0215@gmail.com>
Date: Fri,  8 Mar 2024 12:10:21 +0000
From: yongsuyoo0215@...il.com
To: mchehab@...nel.org,
	yongsuyoo0215@...il.com,
	v4bel@...ori.io,
	linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] media: dvb_ca_en50221: Fix a bug for detecting CI MODULE

From: Yongsu yoo <yongsuyoo0215@...il.com>

Signed-off-by:Yongsu Yoo <yongsuyoo0215@...il.com>

In source/drivers/media/dvb-core/dvb_ca_en50221.c, if the CA_RESET
ioctl is called, the dvb_ca_en50221_slot_shutdown will also be called.
Inside of the dvb_ca_en50221_slot_shutdown,
the ca->slot_info[slot].slot_state will become DVB_CA_SLOTSTATE_NONE.
In the most of cases, the ca->slot_info[slot].slot_state will quickly
becomes restored to other states by the subsequent operations of the
thread dvb_ca_en50221_thread_state_machine.
But in some rare cases, when the CA_GET_SLOT_INFO ioctl is immediately
called after the CA_RESET ioctl is called, the
the ca->slot_info[slot].slot_state can still remains at
DVB_CA_SLOTSTATE_NONE, and this causes CA_GET_SLOT_INFO ioctl not to
return CA_CI_MODULE_PRESENT as info->flags even if CA_CI_MODULE is
really connected on TV. This means that the CA_GET_SLOT_INFO ioctl
does not return right informtion. This is a Bug. We fix this bug.
---
 drivers/media/dvb-core/dvb_ca_en50221.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c
index baf64540dc00..8d37c3c13227 100644
--- a/drivers/media/dvb-core/dvb_ca_en50221.c
+++ b/drivers/media/dvb-core/dvb_ca_en50221.c
@@ -1403,6 +1403,10 @@ static int dvb_ca_en50221_io_do_ioctl(struct file *file,
 		    (sl->slot_state != DVB_CA_SLOTSTATE_INVALID)) {
 			info->flags = CA_CI_MODULE_PRESENT;
 		}
+		if ((sl->slot_state == DVB_CA_SLOTSTATE_NONE) &&
+		    (sl->camchange_type == DVB_CA_EN50221_CAMCHANGE_INSERTED)) {
+			info->flags = CA_CI_MODULE_PRESENT;
+	     	}
 		if (sl->slot_state == DVB_CA_SLOTSTATE_RUNNING)
 			info->flags |= CA_CI_MODULE_READY;
 		break;
-- 
2.17.1