From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 27CDD21CFA5FB for ; Wed, 16 Aug 2017 08:34:12 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C5859285C1; Wed, 16 Aug 2017 15:36:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C5859285C1 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-59.phx2.redhat.com [10.3.116.59]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7D4C660BE6; Wed, 16 Aug 2017 15:36:36 +0000 (UTC) To: Brijesh Singh , edk2-devel-01 Cc: Ard Biesheuvel , Heyi Guo , Star Zeng References: <20170816121040.15757-1-lersek@redhat.com> <20170816121040.15757-2-lersek@redhat.com> From: Laszlo Ersek Message-ID: Date: Wed, 16 Aug 2017 17:36:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 16 Aug 2017 15:36:37 +0000 (UTC) Subject: Re: [PATCH 1/1] ArmVirtPkg/FdtPL011SerialPortLib: call PL011UartLib in all SerialPortLib APIs X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Aug 2017 15:34:12 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 08/16/17 17:03, Brijesh Singh wrote: > Hi Laszlo, > > Thanks for the patch. > > > On 08/16/2017 07:10 AM, Laszlo Ersek wrote: >> With the SerialDxe change in commit 4cf3f37c87ba ("MdeModulePkg >> SerialDxe: >> Process timeout consistently in SerialRead", 2017-07-18), setting >> EFI_SERIAL_INPUT_BUFFER_EMPTY in the "Control" output parameter, in the >> GetControl() SerialPortLib function, is no longer a "small optimization". >> Namely, due to the SerialDxe change, the GetOneKeyFromSerial() call in >> TerminalDxe's TerminalConInTimerHandler() can take very long if the input >> queue is empty, even if GetOneKeyFromSerial()'s return value causes the >> loop to be exited right after, in the first iteration. >> >> This issue causes a boot hang in ArmVirtQemu: with the input queue empty, >> TerminalConInTimerHandler() takes so long to return that, by the time it >> returns, there's another execution queued already (due to the associated >> timer event being signaled meanwhile). The boot process is stuck in the >> timer event handler. >> >> Therefore even the first GetOneKeyFromSerial() iteration must be >> prevented >> in TerminalConInTimerHandler() if the input queue is empty, and that >> requires implementing GetControl() for real. >> >> Implement the SetAttributes(), SetControl() and GetControl() APIs (of >> SerialPortExtLib origin) in FdtPL011SerialPortLib with calls to matching >> PL011UartLib functions. This follows the example of >> "ArmPlatformPkg/Library/PL011SerialPortLib" and also matches Star's >> original idea under [1]. >> >> The patch can be considered a continuation of commit ad7f6bc2e116 >> ("ArmVirtPkg: Use SerialDxe in MdeModulePkg instead of EmbeddedPkg", >> 2015-11-26), based on the mailing list threads [1] [2] [3]. >> >> [1] >> http://mid.mail-archive.com/1447752930-32880-12-git-send-email-star.zeng@intel.com >> >> [2] >> http://mid.mail-archive.com/1448243067-1880-12-git-send-email-star.zeng@intel.com >> >> [3] >> http://mid.mail-archive.com/b748580c-cb51-32c9-acf9-780841ef15da@redhat.com >> >> >> Cc: Ard Biesheuvel >> Cc: Brijesh Singh >> Cc: Heyi Guo >> Cc: Star Zeng >> Originally-suggested-by: Star Zeng >> Reported-by: Brijesh Singh >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Laszlo Ersek >> --- > > > I can confirm that with this patch I am able to boot to the UEFI shell > prompt. > > Tested-by: Brijesh Singh > Thank you Ard and Brijesh; I'll hold off pushing the patch until tomorrow, to see if Heyi and Star want to comment. Thanks! Laszlo