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From:   John Stultz <john.stultz@linaro.org>
To:     lkml <linux-kernel@vger.kernel.org>
Cc:     John Stultz <john.stultz@linaro.org>,
        Rakesh Pillai <pillair@qti.qualcomm.com>,
        Govind Singh <govinds@codeaurora.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Niklas Cassel <niklas.cassel@linaro.org>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        Amit Pundir <amit.pundir@linaro.org>,
        Brian Norris <briannorris@chromium.org>,
        Kalle Valo <kvalo@codeaurora.org>, ath10k@lists.infradead.org
Subject: [PATCH] wireless: ath10k: Return early in ath10k_qmi_event_server_exit() to avoid hard crash on reboot
Date:   Tue,  2 Jun 2020 05:25:33 +0000
Message-Id: <20200602052533.15048-1-john.stultz@linaro.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Ever since 5.7-rc1, if we call
ath10k_qmi_remove_msa_permission(), the db845c hard crashes on
reboot, resulting in the device getting stuck in the usb crash
debug mode and not coming back up wihthout a hard power off.

This hack avoids the issue by returning early in
ath10k_qmi_event_server_exit().

A better solution is very much desired!

Feedback and suggestions welcome!

Cc: Rakesh Pillai <pillair@qti.qualcomm.com>
Cc: Govind Singh <govinds@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Niklas Cassel <niklas.cassel@linaro.org>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: ath10k@lists.infradead.org
Reported-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 drivers/net/wireless/ath/ath10k/qmi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/qmi.c b/drivers/net/wireless/ath/ath10k/qmi.c
index 85dce43c5439..ab38562ce1cb 100644
--- a/drivers/net/wireless/ath/ath10k/qmi.c
+++ b/drivers/net/wireless/ath/ath10k/qmi.c
@@ -854,6 +854,11 @@ static void ath10k_qmi_event_server_exit(struct ath10k_qmi *qmi)
 	struct ath10k *ar = qmi->ar;
 	struct ath10k_snoc *ar_snoc = ath10k_snoc_priv(ar);
 
+	/*
+	 * HACK: Calling ath10k_qmi_remove_msa_permission causes
+	 * hardware to hard crash on reboot
+	 */
+	return;
 	ath10k_qmi_remove_msa_permission(qmi);
 	ath10k_core_free_board_files(ar);
 	if (!test_bit(ATH10K_SNOC_FLAG_UNREGISTERING, &ar_snoc->flags))
-- 
2.17.1