Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757374AbaKTOr4 (ORCPT ); Thu, 20 Nov 2014 09:47:56 -0500 Received: from mail-ig0-f169.google.com ([209.85.213.169]:52255 "EHLO mail-ig0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756291AbaKTOry (ORCPT ); Thu, 20 Nov 2014 09:47:54 -0500 MIME-Version: 1.0 In-Reply-To: <20141120085750.GB23043@ulmo> References: <1416004955-28749-1-git-send-email-hali@codeaurora.org> <20141120085750.GB23043@ulmo> Date: Thu, 20 Nov 2014 09:47:53 -0500 Message-ID: Subject: Re: [PATCH 1/2] drm/msm: Register irq handler for each sub-system in mdss From: Rob Clark To: Thierry Reding Cc: Hai Li , linux-arm-msm , Linux Kernel Mailing List , "dri-devel@lists.freedesktop.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 20, 2014 at 3:57 AM, Thierry Reding wrote: > On Sun, Nov 16, 2014 at 09:18:47AM -0500, Rob Clark wrote: >> On Fri, Nov 14, 2014 at 5:42 PM, Hai Li wrote: >> > All the sub-systems in mdss share the same irq. This change provides >> > the sub-systems with the interfaces to register/unregister their own >> > irq handlers. >> > >> > With this change, struct mdp5_kms does not have to keep the hdmi or >> > edp context. >> > >> >> So, I think the point of this is to better deal w/ different hw >> variants which do or do-not have hdmi, edp, dsi, etc.. >> >> But, just playing devil's advocate here, it seems like it would be >> simpler to instead just do something like: >> >> if (priv->hdmi && (intr & MDP5_HW_INTR_STATUS_INTR_HDMI)) >> hdmi_irq(0, priv->hdmi); >> >> if (priv->edp && (intr & MDP5_HW_INTR_STATUS_INTR_EDP)) >> edp_irq(0, priv->edp); >> >> ... etc ... >> >> It is a little less elegant. But it is also less lines of code. I >> guess there will be plenty of necessary complexity as we add support >> for all mdp5 features. So avoiding some unnecessary complexity might >> be a good thing in the long run. >> >> If we really did want to make it more dynamic, we could always extend >> 'struct mdp_irq' to take both an irq mask and an initiator id, I >> suppose. I'm not sure if that is overkill. AFAICT we really only >> have 5 different subsystems to dispatch to (mdp5 itself, and >> dsi0/dsi1/hdmi/edp), so simply adding some if-not-null checks in >> mdp5_irq() seems pretty reasonable to me. > > To me this just seems like a regular interrupt multiplexer, so > implementing it as an irq_chip would be the most appropriate. That way > you get all the goodness of a well-tested code base for free and you can > simply pass in the request_{threaded_,}irq()'s dev parameter. yup, that is what I did here: http://cgit.freedesktop.org/~robclark/linux/commit/?h=msm-next&id=d9a7093329225ae29bae370823af13290b133a7e there is a bit of awkwardness related to threaded handlers.. for now I don't need threaded handlers so the solution was to not use them > Thierry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/