From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21FE16FA0 for ; Mon, 16 Jan 2023 17:11:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CEC8C433D2; Mon, 16 Jan 2023 17:11:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673889093; bh=FuJT1FqsvOmYhKSqdCDvdA9Ct4jhwfNsFiyxRYTHfFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q8tbDLobTkt8KUk+9apVQPQ/Z9bcSrMXL9gm2CjzGXRE6uicbZfPH9bRA4h9303MW 90xdnJrL2S5488O61IDsiRyDg1Z51MsTfyLOTsqk6kjGVEtyNXfUX11qRAV71ftK9d pH72g6bqnZuqPFH++xyT19Jc2vJr4hjvTIqt2/sA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thinh Nguyen , Ferry Toth Subject: [PATCH 4.14 256/338] usb: dwc3: core: defer probe on ulpi_read_id timeout Date: Mon, 16 Jan 2023 16:52:09 +0100 Message-Id: <20230116154832.240093795@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154820.689115727@linuxfoundation.org> References: <20230116154820.689115727@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ferry Toth commit 63130462c919ece0ad0d9bb5a1f795ef8d79687e upstream. Since commit 0f0101719138 ("usb: dwc3: Don't switch OTG -> peripheral if extcon is present"), Dual Role support on Intel Merrifield platform broke due to rearranging the call to dwc3_get_extcon(). It appears to be caused by ulpi_read_id() masking the timeout on the first test write. In the past dwc3 probe continued by calling dwc3_core_soft_reset() followed by dwc3_get_extcon() which happend to return -EPROBE_DEFER. On deferred probe ulpi_read_id() finally succeeded. Due to above mentioned rearranging -EPROBE_DEFER is not returned and probe completes without phy. On Intel Merrifield the timeout on the first test write issue is reproducible but it is difficult to find the root cause. Using a mainline kernel and rootfs with buildroot ulpi_read_id() succeeds. As soon as adding ftrace / bootconfig to find out why, ulpi_read_id() fails and we can't analyze the flow. Using another rootfs ulpi_read_id() fails even without adding ftrace. We suspect the issue is some kind of timing / race, but merely retrying ulpi_read_id() does not resolve the issue. As we now changed ulpi_read_id() to return -ETIMEDOUT in this case, we need to handle the error by calling dwc3_core_soft_reset() and request -EPROBE_DEFER. On deferred probe ulpi_read_id() is retried and succeeds. Fixes: ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT") Cc: stable@vger.kernel.org Acked-by: Thinh Nguyen Signed-off-by: Ferry Toth Link: https://lore.kernel.org/r/20221205201527.13525-3-ftoth@exalondelft.nl Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -801,8 +801,13 @@ static int dwc3_core_init(struct dwc3 *d if (!dwc->ulpi_ready) { ret = dwc3_core_ulpi_init(dwc); - if (ret) + if (ret) { + if (ret == -ETIMEDOUT) { + dwc3_core_soft_reset(dwc); + ret = -EPROBE_DEFER; + } goto err0; + } dwc->ulpi_ready = true; }