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 8558114BFB0; Tue, 9 Jul 2024 09:32:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720517570; cv=none; b=PnL4Aoag7FWmU9emkczUhD6un5zGnYnpVK6nyN2CWAz0a7+hPAS8xtp5T7EjzOFas+v8NpolHQ66d/Gy4eM0pczRDZiN7OQlh3v9PTU0v+rgw98oi/KnMcqw7T8xeX+w7QlzkJQYToXTH+ZuU8LtNAMOj58DXeB1eLw6Rm/+Ucg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720517570; c=relaxed/simple; bh=hg2hGF7K4KQBhvolAaT0MrUalgjsW8G+lwl6c2ZWnek=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DDFNhbgXfydo46FZcSS9r9VjkjCnOuJ2qsmmLZZ0qjkTLjfooNmBQ91v4S5Y78CKxk806fAwN547BRQdz3bvbJEaJQbWbQkMwXNUOFDBY+dg8rZTLOA+6/FHW0atTaLU0BLTwr5s9vK+5QfI/prkOfs8YttNkb7/MBwplnuiOTc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YJJgeAyK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YJJgeAyK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2544FC3277B; Tue, 9 Jul 2024 09:32:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720517570; bh=hg2hGF7K4KQBhvolAaT0MrUalgjsW8G+lwl6c2ZWnek=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YJJgeAyKodBDS56LhLzxVYex44QWx+xcX8kFf1aRnTfsuzgmWJWp3V9eEXmLniWPC NYpfcCJg/pJch7EpS0bNwdfNSFAB3NQVMrINZTBsaT2bRMpEJcZYeot5dhkiYnE6cM YSq8OVrhe5a9cyfpTASGlDu/vog8W/M1BTQWLQCyX0oGeDdgnEm5OQWKHqwm0DRxGa E5V0Jl4OXIJHuLOsM4QL/hVFqg/omUMWJydnLNN6nPUVhjNxpDZSpTnWpnjdoWhiaH NXKptMNhH9CR3Tbwz31zP6+UxqxqJWcanilcXQzpdfICS7w7ksONJsmDw157kt0atr hm1AAhU1eZ1aA== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1sR7DT-000000005RF-2YpH; Tue, 09 Jul 2024 11:32:56 +0200 Date: Tue, 9 Jul 2024 11:32:55 +0200 From: Johan Hovold To: Doug Anderson Cc: Greg Kroah-Hartman , Johan Hovold , Jiri Slaby , Konrad Dybcio , Bjorn Andersson , linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/3] serial: qcom-geni: fix lockups Message-ID: References: <20240704101805.30612-1-johan+linaro@kernel.org> <2024070445-stunner-scrawny-1b03@gregkh> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hi Doug, Hope you had a good holiday. On Mon, Jul 08, 2024 at 04:57:55PM -0700, Doug Anderson wrote: > On Thu, Jul 4, 2024 at 3:31 AM Greg Kroah-Hartman > wrote: > > > > On Thu, Jul 04, 2024 at 12:18:02PM +0200, Johan Hovold wrote: > > > Since 6.10-rc1, Qualcomm machines with a serial port can easily lock up > > > hard, for example, when stopping a getty on reboot. > > > > > > This was triggered by the kfifo conversion, which turned an existing bug > > > that caused the driver to print discarded characters after a buffer > > > flush into a hard lockup. > > > > > > This series fixes the regression and a related soft lockup issue that > > > can be triggered on software flow control and on suspend. > > > > > > Doug has posted an alternative series of fixes here that depends on > > > reworking the driver a fair bit here: > > > > > > https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ > > > > > > This rework has a significant impact on performance on some platforms, > > > but fortunately it seems such a rework can be avoided. > > > > > > There are further bugs in the console code (e.g. that can lead to lost > > > characters) that this series does not address, but those can be fixed > > > separately (and I've started working on that). > > > > I'll take these now, thanks! > > Are you going to continue to work on the driver? There are still some > pretty bad bugs including ones that are affecting Collabora's test > labs. Unless you want to try to tackle it some other way, I'm going to > keep pushing for something like my original series to land. I can > re-post them atop your patches since they've landed. This will regress > your performance but correctness trumps performance. Yes, I have a working fix for the console issue that could lead to lost characters. I need to spend some time on other things this week, but I intend to follow with fixes for the remaining issues as well. Johan