Commit 5306d4b7 authored May 11, 2020 by Udipto Goswami Committed by Gerrit - the friendly Code Review server Jun 12, 2020

usb: f_qdss: Return -EINVAL instead of -EAGAIN if debug_inface is enabled



Currently if a target uses a composition where both ctrl & data
interface exists, then debug_inface is enabled from userspace. The
f_qdss driver checks for debug_inface_enabled in alloc_req. If the
variable is set then it populates the ctrl_write_pool instead of
data_write_pool. Due to this when qdss_write is called it finds
data_write_pool empty & it will return error message.
However, coresight driver will still request continuously for
qdss_write irrespective of ctrl or data pool. This eventually results
in excessive logging & the device might crash giving watchdog bark
error.

To avoid continuous request, instead of returning -EAGAIN check for
debug_inface_enabled along with empty status of ctrl_data_pool,
data_write_pool and returning -EINVAL.

Change-Id: I8cc6f0f4f2d2b880326c2322d5d907b332ab771b
Signed-off-by: Udipto Goswami <ugoswami@codeaurora.org>

parent 757f1d14

drivers/usb/gadget/function/f_qdss.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -854,8 +854,22 @@ int usb_qdss_write(struct usb_qdss_ch ch, struct qdss_request d_req)
		return -EIO;
		}

		/* If data_write_pool is empty & debug inface is set
		* then return -EINVAL instead of -EAGAIN.
		* qdss_write is expecting data_write_pool to
		* be populated. But data_write_pool is populated only
		* when debug_inface_enbled is not set.
		*/
		if (list_empty(&qdss->data_write_pool) &&
		qdss->debug_inface_enabled) {
		pr_err("%s:error: Invalid operation.\n", __func__);
		spin_unlock_irqrestore(&qdss->lock, flags);
		return -EINVAL;
		}

		if (list_empty(&qdss->data_write_pool)) {
		pr_err("error: usb_qdss_data_write list is empty\n");
		pr_err_ratelimited(
		"error: usb_qdss_data_write list is empty\n");
		spin_unlock_irqrestore(&qdss->lock, flags);
		return -EAGAIN;
		}