From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 719ABC433E0 for ; Fri, 26 Feb 2021 08:00:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21A7F64EDC for ; Fri, 26 Feb 2021 08:00:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230079AbhBZIAl (ORCPT ); Fri, 26 Feb 2021 03:00:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:52370 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbhBZIAd (ORCPT ); Fri, 26 Feb 2021 03:00:33 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DD4F3AAAE; Fri, 26 Feb 2021 07:59:51 +0000 (UTC) Subject: Re: [PATCH v4] drm: Use USB controller's DMA mask when importing dmabufs To: daniel@ffwll.ch, airlied@linux.ie, maarten.lankhorst@linux.intel.com, mripard@kernel.org, sumit.semwal@linaro.org, christian.koenig@amd.com, gregkh@linuxfoundation.org, hdegoede@redhat.com, sean@poorly.run, noralf@tronnes.org, stern@rowland.harvard.edu Cc: stable@vger.kernel.org, dri-devel@lists.freedesktop.org, Christoph Hellwig References: <20210224092304.29932-1-tzimmermann@suse.de> From: Thomas Zimmermann Message-ID: Date: Fri, 26 Feb 2021 08:59:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210224092304.29932-1-tzimmermann@suse.de> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="6e9K8dMXU0lJ77IHXdrcRYc7Zhg3KhCLW" Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --6e9K8dMXU0lJ77IHXdrcRYc7Zhg3KhCLW Content-Type: multipart/mixed; boundary="Dq8wcrgO1lNZQieHaRiYicMoWZ1kNSVEY"; protected-headers="v1" From: Thomas Zimmermann To: daniel@ffwll.ch, airlied@linux.ie, maarten.lankhorst@linux.intel.com, mripard@kernel.org, sumit.semwal@linaro.org, christian.koenig@amd.com, gregkh@linuxfoundation.org, hdegoede@redhat.com, sean@poorly.run, noralf@tronnes.org, stern@rowland.harvard.edu Cc: stable@vger.kernel.org, dri-devel@lists.freedesktop.org, Christoph Hellwig Message-ID: Subject: Re: [PATCH v4] drm: Use USB controller's DMA mask when importing dmabufs References: <20210224092304.29932-1-tzimmermann@suse.de> In-Reply-To: <20210224092304.29932-1-tzimmermann@suse.de> --Dq8wcrgO1lNZQieHaRiYicMoWZ1kNSVEY Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Greg, do you have comments on this patch? Am 24.02.21 um 10:23 schrieb Thomas Zimmermann: > USB devices cannot perform DMA and hence have no dma_mask set in their > device structure. Therefore importing dmabuf into a USB-based driver > fails, which breaks joining and mirroring of display in X11. >=20 > For USB devices, pick the associated USB controller as attachment devic= e. > This allows the DRM import helpers to perform the DMA setup. If the DMA= > controller does not support DMA transfers, we're out of luck and cannot= > import. Our current USB-based DRM drivers don't use DMA, so the actual > DMA device is not important. >=20 > Drivers should use DRM_GEM_SHMEM_DROVER_OPS_USB to initialize their > instance of struct drm_driver. >=20 > Tested by joining/mirroring displays of udl and radeon un der Gnome/X11= =2E >=20 > v4: > * implement workaround with USB helper functions (Greg) > * use struct usb_device->bus->sysdev as DMA device (Takashi) > v3: > * drop gem_create_object > * use DMA mask of USB controller, if any (Daniel, Christian, Noralf) > v2: > * move fix to importer side (Christian, Daniel) > * update SHMEM and CMA helpers for new PRIME callbacks >=20 > Signed-off-by: Thomas Zimmermann > Fixes: 6eb0233ec2d0 ("usb: don't inherity DMA properties for USB device= s") > Cc: Christoph Hellwig > Cc: Greg Kroah-Hartman > Cc: # v5.10+ > --- > drivers/gpu/drm/drm_prime.c | 38 +++++++++++++++++++++++++++++= + > drivers/gpu/drm/tiny/gm12u320.c | 2 +- > drivers/gpu/drm/udl/udl_drv.c | 2 +- > drivers/usb/core/usb.c | 29 +++++++++++++++++++++++ > include/drm/drm_gem_shmem_helper.h | 13 ++++++++++ > include/drm/drm_prime.h | 5 ++++ > include/linux/usb.h | 3 +++ > 7 files changed, 90 insertions(+), 2 deletions(-) >=20 > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c > index 2a54f86856af..15c82088ab4c 100644 > --- a/drivers/gpu/drm/drm_prime.c > +++ b/drivers/gpu/drm/drm_prime.c > @@ -29,6 +29,7 @@ > #include > #include > #include > +#include > =20 > #include > #include > @@ -1055,3 +1056,40 @@ void drm_prime_gem_destroy(struct drm_gem_object= *obj, struct sg_table *sg) > dma_buf_put(dma_buf); > } > EXPORT_SYMBOL(drm_prime_gem_destroy); > + > +/** > + * drm_gem_prime_import_usb - helper library implementation of the imp= ort callback for USB devices > + * @dev: drm_device to import into > + * @dma_buf: dma-buf object to import > + * > + * This is an implementation of drm_gem_prime_import() for USB-based d= evices. > + * USB devices cannot perform DMA directly. This function selects the = USB host > + * controller as DMA device instead. Drivers can use this as their > + * &drm_driver.gem_prime_import implementation. > + * > + * See also drm_gem_prime_import(). > + */ > +#ifdef CONFIG_USB > +struct drm_gem_object *drm_gem_prime_import_usb(struct drm_device *dev= , > + struct dma_buf *dma_buf) > +{ > + struct usb_device *udev; > + struct device *dmadev; > + struct drm_gem_object *obj; > + > + if (!dev_is_usb(dev->dev)) > + return ERR_PTR(-ENODEV); > + udev =3D interface_to_usbdev(to_usb_interface(dev->dev)); > + > + dmadev =3D usb_get_dma_device(udev); > + if (drm_WARN_ONCE(dev, !dmadev, "buffer sharing not supported")) > + return ERR_PTR(-ENODEV); > + > + obj =3D drm_gem_prime_import_dev(dev, dma_buf, dmadev); > + > + put_device(dmadev); > + > + return obj; > +} > +EXPORT_SYMBOL(drm_gem_prime_import_usb); > +#endif > diff --git a/drivers/gpu/drm/tiny/gm12u320.c b/drivers/gpu/drm/tiny/gm1= 2u320.c > index 0b4f4f2af1ef..99e7bd36a220 100644 > --- a/drivers/gpu/drm/tiny/gm12u320.c > +++ b/drivers/gpu/drm/tiny/gm12u320.c > @@ -611,7 +611,7 @@ static const struct drm_driver gm12u320_drm_driver = =3D { > .minor =3D DRIVER_MINOR, > =20 > .fops =3D &gm12u320_fops, > - DRM_GEM_SHMEM_DRIVER_OPS, > + DRM_GEM_SHMEM_DRIVER_OPS_USB, > }; > =20 > static const struct drm_mode_config_funcs gm12u320_mode_config_funcs = =3D { > diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_dr= v.c > index 9269092697d8..2db483b2b199 100644 > --- a/drivers/gpu/drm/udl/udl_drv.c > +++ b/drivers/gpu/drm/udl/udl_drv.c > @@ -39,7 +39,7 @@ static const struct drm_driver driver =3D { > =20 > /* GEM hooks */ > .fops =3D &udl_driver_fops, > - DRM_GEM_SHMEM_DRIVER_OPS, > + DRM_GEM_SHMEM_DRIVER_OPS_USB, > =20 > .name =3D DRIVER_NAME, > .desc =3D DRIVER_DESC, > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c > index 8f07b0516100..253bf71780fd 100644 > --- a/drivers/usb/core/usb.c > +++ b/drivers/usb/core/usb.c > @@ -748,6 +748,35 @@ void usb_put_intf(struct usb_interface *intf) > } > EXPORT_SYMBOL_GPL(usb_put_intf); > =20 > +/** > + * usb_get_dma_device - acquire a reference on the usb device's DMA en= dpoint > + * @udev: usb device > + * > + * While a USB device cannot perform DMA operations by itself, many US= B > + * controllers can. A call to usb_get_dma_device() returns the DMA end= point > + * for the given USB device, if any. The returned device structure sho= uld be > + * released with put_device(). > + * > + * Returns: A reference to the usb device's DMA endpoint; or NULL if n= one > + * exists. > + */ > +struct device *usb_get_dma_device(struct usb_device *udev) > +{ > + struct device *dmadev; > + > + if (!udev->bus) > + return NULL; > + > + dmadev =3D get_device(udev->bus->sysdev); > + if (!dmadev || !dmadev->dma_mask) { > + put_device(dmadev); > + return NULL; > + } > + > + return dmadev; > +} > +EXPORT_SYMBOL_GPL(usb_get_dma_device); > + > /* USB device locking > * > * USB devices and interfaces are locked using the semaphore in their= > diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_s= hmem_helper.h > index 434328d8a0d9..09d12f632cad 100644 > --- a/include/drm/drm_gem_shmem_helper.h > +++ b/include/drm/drm_gem_shmem_helper.h > @@ -162,4 +162,17 @@ struct sg_table *drm_gem_shmem_get_pages_sgt(struc= t drm_gem_object *obj); > .gem_prime_mmap =3D drm_gem_prime_mmap, \ > .dumb_create =3D drm_gem_shmem_dumb_create > =20 > +#ifdef CONFIG_USB > +/** > + * DRM_GEM_SHMEM_DRIVER_OPS_USB - Default shmem GEM operations for USB= devices > + * > + * This macro provides a shortcut for setting the shmem GEM operations= in > + * the &drm_driver structure. Drivers for USB-based devices should use= this > + * macro instead of &DRM_GEM_SHMEM_DRIVER_OPS. > + */ > +#define DRM_GEM_SHMEM_DRIVER_OPS_USB \ > + DRM_GEM_SHMEM_DRIVER_OPS, \ > + .gem_prime_import =3D drm_gem_prime_import_usb > +#endif > + > #endif /* __DRM_GEM_SHMEM_HELPER_H__ */ > diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h > index 54f2c58305d2..b42e07edd9e6 100644 > --- a/include/drm/drm_prime.h > +++ b/include/drm/drm_prime.h > @@ -110,4 +110,9 @@ int drm_prime_sg_to_page_array(struct sg_table *sgt= , struct page **pages, > int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *= addrs, > int max_pages); > =20 > +#ifdef CONFIG_USB > +struct drm_gem_object *drm_gem_prime_import_usb(struct drm_device *dev= , > + struct dma_buf *dma_buf); > +#endif > + > #endif /* __DRM_PRIME_H__ */ > diff --git a/include/linux/usb.h b/include/linux/usb.h > index 7d72c4e0713c..a9bd698c8839 100644 > --- a/include/linux/usb.h > +++ b/include/linux/usb.h > @@ -711,6 +711,7 @@ struct usb_device { > unsigned use_generic_driver:1; > }; > #define to_usb_device(d) container_of(d, struct usb_device, dev) > +#define dev_is_usb(d) ((d)->bus =3D=3D &usb_bus_type) > =20 > static inline struct usb_device *interface_to_usbdev(struct usb_inter= face *intf) > { > @@ -746,6 +747,8 @@ extern int usb_lock_device_for_reset(struct usb_dev= ice *udev, > extern int usb_reset_device(struct usb_device *dev); > extern void usb_queue_reset_device(struct usb_interface *dev); > =20 > +extern struct device *usb_get_dma_device(struct usb_device *udev); > + > #ifdef CONFIG_ACPI > extern int usb_acpi_set_power_state(struct usb_device *hdev, int inde= x, > bool enable); >=20 --=20 Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany (HRB 36809, AG N=C3=BCrnberg) Gesch=C3=A4ftsf=C3=BChrer: Felix Imend=C3=B6rffer --Dq8wcrgO1lNZQieHaRiYicMoWZ1kNSVEY-- --6e9K8dMXU0lJ77IHXdrcRYc7Zhg3KhCLW Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsF5BAABCAAjFiEExndm/fpuMUdwYFFolh/E3EQov+AFAmA4qnYFAwAAAAAACgkQlh/E3EQov+An hQ/+KwccQGtHg+1C4ng+lrWHQimvio7WKE6DnapDgBOeusDM6xOUB17hfkSjQpU2D/kmzwqTIxNK 6v6baIBrI3QSXuX8+4I5W/tngl+41zFNMYE2tld6u+8MkXqNf4M9d2E4OH37Bhy2MfD2omavYPMg AY9JQz/tiOkim7O2E31xChmaTQ2zB9dinZI/ze1E8JWyr9s98AGTPV5q8ZJ2khlpRZjCNzSGZh1F 5D5768pDqFYb6sRbmDwl+IPit5n97hOT2PUoNY1EOQ7dRkhg0GrsSD6GKKvVmQiaYu2KCY9aDaqu djmVHUKOC1eNOxR5Ep2zeYbLkPDIebzQ9oFownH5FPBsjvLpl85j0U68CbNe0p6Eh9AUM91UMWVD BghvL3jfbzjE2LaG6jMtWivSMW2B3peRRab6JQcrqdzwGrMKDamqkdc5l804ojoOBxRHLobvCI4g O9rbFvWhxI2Zf5wV5flknu1b7PUiBe53hJHZoszcihVtXQvi/xiReNnBMZZ2KEY1nHx/PJADekKp sNC7o2bn2F32d3EobKDJRD6tLEv9CdSQnDOK2aIZg53hgxSWc/VYDPPQoFSfysuN9UsBgj1YQfbr 8rXFvzZH+hfP3N+iZ4AKKttSWTEUUHPFvoxG+ijgg7K91UQyM+FTz+VYCN0C7ZrBFTuXV3tneij4 Lbg= =SEjD -----END PGP SIGNATURE----- --6e9K8dMXU0lJ77IHXdrcRYc7Zhg3KhCLW--