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From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH 13/18] usb: host: ehci: Add a comment explaing IOC setting for data
Date: Wed, 22 May 2019 00:34:09 -0700	[thread overview]
Message-ID: <20190522073414.9308-14-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <20190522073414.9308-1-andrew.smirnov@gmail.com>

Add a comment explaining the rationale behinde QT_TOKEN_IOC(req ==
NULL).

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 drivers/usb/host/ehci-hcd.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index f0d899e82..a6f497925 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -362,6 +362,15 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer,
 
 		ret = ehci_prepare_qtd(ehci->dev,
 				       td, QT_TOKEN_DT(toggle) |
+				       /*
+					* We only want this qTD to
+					* generate an interrupt if
+					* this is a BULK
+					* request. Otherwise, we'll
+					* rely on following status
+					* stage qTD's IOC to notify us
+					* that transfer is complete
+					*/
 				       QT_TOKEN_IOC(req == NULL) |
 				       QT_TOKEN_PID(pid),
 				       buffer, length,
-- 
2.21.0


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  parent reply	other threads:[~2019-05-22  7:34 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22  7:33 [PATCH 00/18] EHCI improvements Andrey Smirnov
2019-05-22  7:33 ` [PATCH 01/18] usb: host: ehci: Do not zero out DMA coherent memory Andrey Smirnov
2019-05-22  7:33 ` [PATCH 02/18] usb: host: ehci: Share code to enable/disable async schedule Andrey Smirnov
2019-05-22  7:33 ` [PATCH 03/18] usb: host: ehci: Use to USBSTS to wait for transfer completion Andrey Smirnov
2019-05-22  7:34 ` [PATCH 04/18] usb: host: ehci: Replace magic number with macros Andrey Smirnov
2019-05-22  7:34 ` [PATCH 05/18] usb: host: ehci: Drop unnecessary cleanup code Andrey Smirnov
2019-05-22  7:34 ` [PATCH 06/18] usb: host: ehci: Introduce ehci_prepare_qtd() Andrey Smirnov
2019-05-22  7:34 ` [PATCH 07/18] usb: host: ehci: Simplify qTD buffer synchronization Andrey Smirnov
2019-05-22  7:34 ` [PATCH 08/18] usb: host: ehci: Simplify ehci_td_buffer() Andrey Smirnov
2019-05-22  7:34 ` [PATCH 09/18] usb: host: ehci: Initialize qTDs explicitly Andrey Smirnov
2019-05-22  7:34 ` [PATCH 10/18] usb: host: ehci: Simplify ehci_submit_async()'s epilogue Andrey Smirnov
2019-05-22  7:34 ` [PATCH 11/18] usb: host: ehci: Drop needless assignments in ehci_submit_async() Andrey Smirnov
2019-05-22  7:34 ` [PATCH 12/18] usb: host: ehci: Use bool to simplify ehci_submit_async() Andrey Smirnov
2019-05-22  7:34 ` Andrey Smirnov [this message]
2019-05-22  7:34 ` [PATCH 14/18] usb: host: ehci: Replace explicit printf() with dev_err() Andrey Smirnov
2019-05-22  7:34 ` [PATCH 15/18] usb: host: ehci: Drop explicit memset() in ehci_init() Andrey Smirnov
2019-05-22  7:34 ` [PATCH 16/18] usb: host: ehci: Treat ehci->qh_list as an array Andrey Smirnov
2019-05-22  7:34 ` [PATCH 17/18] ush: host: ehci: Simplify QH initialization in ehci_submit_async() Andrey Smirnov
2019-05-22  7:34 ` [PATCH 18/18] usb: host: ehci: Allocate only NUM_QH queue heads for qh_list Andrey Smirnov
2019-05-23  7:57 ` [PATCH 00/18] EHCI improvements Sascha Hauer

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