Messages in this thread | | | Date | Tue, 18 Oct 2022 15:10:38 +0100 | Subject | Re: [PATCH v3 6/6] usb: gadget: uvc: add configfs option for sg support | From | Dan Scally <> |
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Hi Michael - again!
On 18/10/2022 15:04, Michael Grzeschik wrote: > Hi Dan! > Hi Dan! > > On Tue, Oct 18, 2022 at 02:27:13PM +0100, Dan Scally wrote: >> Hi Dan >> >> On 17/10/2022 21:54, Dan Vacura wrote: >>> The scatter gather support doesn't appear to work well with some UDC >>> hw. >>> Add the ability to turn on the feature depending on the controller in >>> use. >>> >>> Signed-off-by: Dan Vacura <w36195@motorola.com> >> >> >> Nitpick: I would call it use_sg everywhere, but either way: > > Or even only "scatter_gather". How does that sound?
I think I prefer use_sg actually, but I don't have a strong feeling either way.
> >> >> Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com> >> >> Tested-by: Daniel Scally <dan.scally@ideasonboard.com> >> >>> --- >>> V1 -> V2: >>> - no change, new patch in serie >>> V2 -> V3: >>> - default on, same as baseline >>> >>> Documentation/ABI/testing/configfs-usb-gadget-uvc | 1 + >>> Documentation/usb/gadget-testing.rst | 2 ++ >>> drivers/usb/gadget/function/f_uvc.c | 2 ++ >>> drivers/usb/gadget/function/u_uvc.h | 1 + >>> drivers/usb/gadget/function/uvc_configfs.c | 2 ++ >>> drivers/usb/gadget/function/uvc_queue.c | 4 ++-- >>> 6 files changed, 10 insertions(+), 2 deletions(-) >>> >>> diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc >>> b/Documentation/ABI/testing/configfs-usb-gadget-uvc >>> index 5dfaa3f7f6a4..839a75fc28ee 100644 >>> --- a/Documentation/ABI/testing/configfs-usb-gadget-uvc >>> +++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc >>> @@ -9,6 +9,7 @@ Description: UVC function directory >>> streaming_interval 1..16 >>> function_name string [32] >>> req_int_skip_div unsigned int >>> + sg_supported 0..1 >>> =================== ============================= >>> What: /config/usb-gadget/gadget/functions/uvc.name/control >>> diff --git a/Documentation/usb/gadget-testing.rst >>> b/Documentation/usb/gadget-testing.rst >>> index f9b5a09be1f4..8e3072d6a590 100644 >>> --- a/Documentation/usb/gadget-testing.rst >>> +++ b/Documentation/usb/gadget-testing.rst >>> @@ -796,6 +796,8 @@ The uvc function provides these attributes in >>> its function directory: >>> function_name name of the interface >>> req_int_skip_div divisor of total requests to aid in >>> calculating >>> interrupt frequency, 0 indicates all interrupt >>> + sg_supported allow for scatter gather to be used if the UDC >>> + hw supports it >>> =================== >>> ================================================ >>> There are also "control" and "streaming" subdirectories, each of >>> which contain >>> diff --git a/drivers/usb/gadget/function/f_uvc.c >>> b/drivers/usb/gadget/function/f_uvc.c >>> index e40ca26b9c55..d08ebe3ffeb2 100644 >>> --- a/drivers/usb/gadget/function/f_uvc.c >>> +++ b/drivers/usb/gadget/function/f_uvc.c >>> @@ -656,6 +656,7 @@ uvc_function_bind(struct usb_configuration *c, >>> struct usb_function *f) >>> (opts->streaming_maxburst + 1)); >>> uvc->config_skip_int_div = opts->req_int_skip_div; >>> + uvc->video.queue.use_sg = opts->sg_supported; > > Why do you set this here? > >>> /* Allocate endpoints. */ >>> ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep); >>> @@ -875,6 +876,7 @@ static struct usb_function_instance >>> *uvc_alloc_inst(void) >>> opts->streaming_interval = 1; >>> opts->streaming_maxpacket = 1024; >>> opts->req_int_skip_div = 4; >>> + opts->sg_supported = 1; >>> snprintf(opts->function_name, sizeof(opts->function_name), "UVC >>> Camera"); >>> ret = uvcg_attach_configfs(opts); >>> diff --git a/drivers/usb/gadget/function/u_uvc.h >>> b/drivers/usb/gadget/function/u_uvc.h >>> index 6f73bd5638ed..5ccced629925 100644 >>> --- a/drivers/usb/gadget/function/u_uvc.h >>> +++ b/drivers/usb/gadget/function/u_uvc.h >>> @@ -25,6 +25,7 @@ struct f_uvc_opts { >>> unsigned int streaming_maxpacket; >>> unsigned int streaming_maxburst; >>> unsigned int req_int_skip_div; >>> + unsigned int sg_supported; >>> unsigned int control_interface; >>> unsigned int streaming_interface; >>> diff --git a/drivers/usb/gadget/function/uvc_configfs.c >>> b/drivers/usb/gadget/function/uvc_configfs.c >>> index 419e926ab57e..3784c0e02d01 100644 >>> --- a/drivers/usb/gadget/function/uvc_configfs.c >>> +++ b/drivers/usb/gadget/function/uvc_configfs.c >>> @@ -2351,6 +2351,7 @@ UVCG_OPTS_ATTR(streaming_interval, >>> streaming_interval, 16); >>> UVCG_OPTS_ATTR(streaming_maxpacket, streaming_maxpacket, 3072); >>> UVCG_OPTS_ATTR(streaming_maxburst, streaming_maxburst, 15); >>> UVCG_OPTS_ATTR(req_int_skip_div, req_int_skip_div, UINT_MAX); >>> +UVCG_OPTS_ATTR(sg_supported, sg_supported, 1); >>> #undef UVCG_OPTS_ATTR >>> @@ -2401,6 +2402,7 @@ static struct configfs_attribute *uvc_attrs[] = { >>> &f_uvc_opts_attr_streaming_maxpacket, >>> &f_uvc_opts_attr_streaming_maxburst, >>> &f_uvc_opts_attr_req_int_skip_div, >>> + &f_uvc_opts_attr_sg_supported, >>> &f_uvc_opts_string_attr_function_name, >>> NULL, >>> }; >>> diff --git a/drivers/usb/gadget/function/uvc_queue.c >>> b/drivers/usb/gadget/function/uvc_queue.c >>> index 02559906a55a..3c7aa5c4bba2 100644 >>> --- a/drivers/usb/gadget/function/uvc_queue.c >>> +++ b/drivers/usb/gadget/function/uvc_queue.c >>> @@ -149,11 +149,11 @@ int uvcg_queue_init(struct uvc_video_queue >>> *queue, struct device *dev, enum v4l2 >>> queue->queue.buf_struct_size = sizeof(struct uvc_buffer); >>> queue->queue.ops = &uvc_queue_qops; >>> queue->queue.lock = lock; >>> - if (cdev->gadget->sg_supported) { >>> + if (queue->use_sg && cdev->gadget->sg_supported) { >>> queue->queue.mem_ops = &vb2_dma_sg_memops; >>> - queue->use_sg = 1; >>> } else { >>> queue->queue.mem_ops = &vb2_vmalloc_memops; >>> + queue->use_sg = false; > > I am unsure, but can you actually not always use vb2_dma_sg_memops. > > With my last patch we always set buf->mem to vb2_plane_vaddr(vb, 0); > > https://lore.kernel.org/linux-usb/20221017221141.3134818-1-m.grzeschik@pengutronix.de/T/#u > > > > The condition to decide if encode_isoc_sg or encode_isoc should then > remain the last place to switch between sg or not. I would hook the > userspace decision in here. > > You can also directly get to opts->scatter_gather by using > > struct f_uvc_opts *opts = fi_to_f_uvc_opts(uvc->func.fi); > > in the function uvcg_video_enable. > >>> } >>> queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY >> > > Thanks, > Michael >
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