From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752405AbeBUIXJ (ORCPT ); Wed, 21 Feb 2018 03:23:09 -0500 Received: from mx2.suse.de ([195.135.220.15]:48660 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752389AbeBUIXI (ORCPT ); Wed, 21 Feb 2018 03:23:08 -0500 Subject: Re: [PATCH 2/9] drm/xen-front: Implement Xen bus state handling To: Oleksandr Andrushchenko , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, daniel.vetter@intel.com, seanpaul@chromium.org, gustavo@padovan.org, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Cc: Oleksandr Andrushchenko References: <1519200222-20623-1-git-send-email-andr2000@gmail.com> <1519200222-20623-3-git-send-email-andr2000@gmail.com> From: Juergen Gross Message-ID: <7b302293-a4ca-0225-576f-0cc33f6f56cb@suse.com> Date: Wed, 21 Feb 2018 09:23:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1519200222-20623-3-git-send-email-andr2000@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/02/18 09:03, Oleksandr Andrushchenko wrote: > From: Oleksandr Andrushchenko > > Initial handling for Xen bus states: implement > Xen bus state machine for the frontend driver according to > the state diagram and recovery flow from display para-virtualized > protocol: xen/interface/io/displif.h. > > Signed-off-by: Oleksandr Andrushchenko > --- > drivers/gpu/drm/xen/xen_drm_front.c | 124 +++++++++++++++++++++++++++++++++++- > drivers/gpu/drm/xen/xen_drm_front.h | 26 ++++++++ > 2 files changed, 149 insertions(+), 1 deletion(-) > create mode 100644 drivers/gpu/drm/xen/xen_drm_front.h > > diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c > index fd372fb464a1..d0306f9d660d 100644 > --- a/drivers/gpu/drm/xen/xen_drm_front.c > +++ b/drivers/gpu/drm/xen/xen_drm_front.c > @@ -24,19 +24,141 @@ > > #include > > +#include "xen_drm_front.h" > + > +static void xen_drv_remove_internal(struct xen_drm_front_info *front_info) > +{ > +} > + > +static int backend_on_initwait(struct xen_drm_front_info *front_info) > +{ > + return 0; > +} > + > +static int backend_on_connected(struct xen_drm_front_info *front_info) > +{ > + return 0; > +} > + > +static void backend_on_disconnected(struct xen_drm_front_info *front_info) > +{ > + xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising); > +} > + > static void backend_on_changed(struct xenbus_device *xb_dev, > enum xenbus_state backend_state) > { > + struct xen_drm_front_info *front_info = dev_get_drvdata(&xb_dev->dev); > + int ret; > + > + DRM_DEBUG("Backend state is %s, front is %s\n", > + xenbus_strstate(backend_state), > + xenbus_strstate(xb_dev->state)); > + > + switch (backend_state) { > + case XenbusStateReconfiguring: > + /* fall through */ > + case XenbusStateReconfigured: > + /* fall through */ > + case XenbusStateInitialised: > + break; > + > + case XenbusStateInitialising: > + /* recovering after backend unexpected closure */ > + backend_on_disconnected(front_info); > + break; > + > + case XenbusStateInitWait: > + /* recovering after backend unexpected closure */ > + backend_on_disconnected(front_info); > + if (xb_dev->state != XenbusStateInitialising) > + break; > + > + ret = backend_on_initwait(front_info); > + if (ret < 0) > + xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); > + else > + xenbus_switch_state(xb_dev, XenbusStateInitialised); > + break; > + > + case XenbusStateConnected: > + if (xb_dev->state != XenbusStateInitialised) > + break; > + > + ret = backend_on_connected(front_info); > + if (ret < 0) > + xenbus_dev_fatal(xb_dev, ret, "initializing DRM driver"); > + else > + xenbus_switch_state(xb_dev, XenbusStateConnected); > + break; > + > + case XenbusStateClosing: > + /* > + * in this state backend starts freeing resources, > + * so let it go into closed state, so we can also > + * remove ours > + */ > + break; > + > + case XenbusStateUnknown: > + /* fall through */ > + case XenbusStateClosed: > + if (xb_dev->state == XenbusStateClosed) > + break; > + > + backend_on_disconnected(front_info); > + break; > + } > } > > static int xen_drv_probe(struct xenbus_device *xb_dev, > const struct xenbus_device_id *id) > { > - return 0; > + struct xen_drm_front_info *front_info; > + > + front_info = devm_kzalloc(&xb_dev->dev, > + sizeof(*front_info), GFP_KERNEL); > + if (!front_info) { > + xenbus_dev_fatal(xb_dev, -ENOMEM, "allocating device memory"); No need for message in case of allocation failure: this is handled in memory allocation already. Juergen