From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [alsa-devel] [PATCH 4/9] ASoC: tegra: add Tegra210 based I2S driver Date: Wed, 22 Jan 2020 09:23:29 +0300 Message-ID: <598fe377-5b95-d30a-eb64-89a645166d42@gmail.com> References: <1579530198-13431-1-git-send-email-spujar@nvidia.com> <1579530198-13431-5-git-send-email-spujar@nvidia.com> <0c571858-d72c-97c2-2d6a-ead6fdde06eb@nvidia.com> <444731da-c4cd-8578-a732-c803eef31ef0@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sameer Pujar , perex-/Fr2/VpizcU@public.gmane.org, tiwai-IBi9RG/b67k@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org, atalambedu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lgirdwood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, viswanathl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, sharadg-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, rlokhande-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mkumard-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, dramesh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org List-Id: linux-tegra@vger.kernel.org 22.01.2020 07:32, Sameer Pujar пишет: [snip] >>>>> +static int tegra210_i2s_remove(struct platform_device *pdev) >>>>> +{ >>>>> +     pm_runtime_disable(&pdev->dev); >>>>> +     if (!pm_runtime_status_suspended(&pdev->dev)) >>>>> +             tegra210_i2s_runtime_suspend(&pdev->dev); >>>> This breaks device's RPM refcounting if it was disabled in the active >>>> state. This code should be removed. At most you could warn about the >>>> unxpected RPM state here, but it shouldn't be necessary. >>> I guess this was added for safety and explicit suspend keeps clock >>> disabled. >>> Not sure if ref-counting of the device matters when runtime PM is >>> disabled and device is removed. >>> I see few drivers using this way. >> It should matter (if I'm not missing something) because RPM should be in >> a wrecked state once you'll try to re-load the driver's module. Likely >> that those few other drivers are wrong. >> >> [snip] > > Once the driver is re-loaded and RPM is enabled, I don't think it would use > the same 'dev' and the corresponding ref count. Doesn't it use the new > counters? > If RPM is not working for some reason, most likely it would be the case > for other > devices. What best driver can do is probably do a force suspend during > removal if > already not done. I would prefer to keep, since multiple drivers still > have it, > unless there is a real harm in doing so. I took a closer look and looks like the counter actually should be reset. Still I don't think that it's a good practice to make changes underneath of RPM, it may strike back. >>>>> +     int rx_fifo_th; >>>> Could rx_fifo_th be negative? >>> rx_fifo_th itself does not take negative values, explicit >>> typecasting> is avoided in "if" condition by declaring this as "int" >> Explicit typecasting isn't needed for integers. > > What I meant was, rx_fifo_th is checked against a 'int' variable in an > "if" condition. What's the problem with comparing of unsigned with signed? Besides, cif_conf.audio_ch > I2S_RX_FIFO_DEPTH can't be ever true, isn't it? I2S_RX_FIFO_DEPTH=64, channels_max=16 Lastly, nothing stops you to make max_th unsigned.