From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Behme Subject: Re: [PATCH 1/5] serial: imx: remove unneeded imx_transmit_buffer() from imx_start_tx() Date: Mon, 12 May 2014 07:45:56 +0200 Message-ID: <53706014.8010203@de.bosch.com> References: <1399648788-26061-1-git-send-email-dean_jenkins@mentor.com> <1399648788-26061-2-git-send-email-dean_jenkins@mentor.com> <537042B5.2040600@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <537042B5.2040600@freescale.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Huang Shijie Cc: "gregkh@linuxfoundation.org" , "s.hauer@pengutronix.de" , "dean_jenkins@mentor.com" , "shawn.guo@freescale.com" , "linux-serial@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" List-Id: linux-serial@vger.kernel.org T24gMTIuMDUuMjAxNCAwNTo0MCwgSHVhbmcgU2hpamllIHdyb3RlOgo+IOS6jiAyMDE05bm0MDXm nIgwOeaXpSAyMzoxOSwgZGVhbl9qZW5raW5zQG1lbnRvci5jb20g5YaZ6YGTOgo+PiBVc2UgaW14 X3N0YXJ0X3R4KCkganVzdCB0byBlbmFibGUgdGhlIFRYIGludGVycnVwdC4gSXQncyB0aGUgam9i IG9mIHRoZQo+PiBUWCBpbnRlcnJ1cHQgSVNSIHRvIGZpbGwgdGhlIHRyYW5zbWl0IGJ1ZmZlciwg dGhlbi4gSWYgdGhlIHRyYW5zbWl0IGJ1ZmZlcgo+PiBpcyBlbXB0eSwgdGhlIFRYIGludGVycnVw dCBzaG91bGQgYmUgZXhlY3V0ZWQgYXMgc29vbiBhcyB0aGUgc3RhcnRfdHgoKQo+PiBlbmFibGVz IHRoZSBpbnRlcnJ1cHQsIHNvIHRoZXJlIGlzIG5vIHJlYXNvbiBmb3IgdGhlIGV4dHJhCj4+IGlt eF90cmFuc21pdF9idWZmZXIoKSBjYWxsLCBoZXJlLiBSZW1vdmUgaXQuCj4gSSBkb24ndCBrbm93 IHdoeSB0aGlzIHBhdGNoIG5lZWRlZD8KPiBXaGF0IHByb2JsZW0gdGhpcyBwYXRjaCBmaXggb3Ig aW1wcm92ZT8KCkFzIHN0YXRlZCBpbiB0aGUgY29tbWl0IG1lc3NhZ2UsIHRoZSBjYWxsIG9mIGlt eF90cmFuc21pdF9idWZmZXIoKSBpc24ndCAKbmVlZGVkIHRoZXJlLCBzbyBpdCBjYW4gYmUgcmVt b3ZlZC4gSS5lLiByZW1vdmUgdW5uZWVkZWQgY29kZS4KCkluIHRoZSBlbmQsIHRoaXMgY2xlYW5z IHVwIHRoZSBwb3NzaWJsZSBsb2NraW5nIHBhdGgsIHNvIHRoYXQgaW4gdGhlIAp0aGlyZCBwYXRj aCB0aGUgbG9ja2luZyBpc3N1ZSBjYW4gYmUgZWFzaWx5IGZpeGVkLgoKQmVzdCByZWdhcmRzCgpE aXJrCgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbGlu dXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5pbmZyYWRl YWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgt YXJtLWtlcm5lbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 From: dirk.behme@de.bosch.com (Dirk Behme) Date: Mon, 12 May 2014 07:45:56 +0200 Subject: [PATCH 1/5] serial: imx: remove unneeded imx_transmit_buffer() from imx_start_tx() In-Reply-To: <537042B5.2040600@freescale.com> References: <1399648788-26061-1-git-send-email-dean_jenkins@mentor.com> <1399648788-26061-2-git-send-email-dean_jenkins@mentor.com> <537042B5.2040600@freescale.com> Message-ID: <53706014.8010203@de.bosch.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 12.05.2014 05:40, Huang Shijie wrote: > ? 2014?05?09? 23:19, dean_jenkins at mentor.com ??: >> Use imx_start_tx() just to enable the TX interrupt. It's the job of the >> TX interrupt ISR to fill the transmit buffer, then. If the transmit buffer >> is empty, the TX interrupt should be executed as soon as the start_tx() >> enables the interrupt, so there is no reason for the extra >> imx_transmit_buffer() call, here. Remove it. > I don't know why this patch needed? > What problem this patch fix or improve? As stated in the commit message, the call of imx_transmit_buffer() isn't needed there, so it can be removed. I.e. remove unneeded code. In the end, this cleans up the possible locking path, so that in the third patch the locking issue can be easily fixed. Best regards Dirk