From: Maxim Devaev mdevaev@gmail.com
[ Upstream commit d7428bc26fc767942c38d74b80299bcd4f01e7cb ]
f_hid provides the OUT Endpoint as only way for receiving reports from the host. SETUP/SET_REPORT method is not supported, and this causes a number of compatibility problems with various host drivers, especially in the case of keyboard emulation using f_hid.
- Some hosts do not support the OUT Endpoint and ignore it, so it becomes impossible for the gadget to receive a report from the host. In the case of a keyboard, the gadget loses the ability to receive the status of the LEDs.
- Some BIOSes/UEFIs can't work with HID devices with the OUT Endpoint at all. This may be due to their bugs or incomplete implementation of the HID standard. For example, absolutely all Apple UEFIs can't handle the OUT Endpoint if it goes after IN Endpoint in the descriptor and require the reverse order (OUT, IN) which is a violation of the standard. Other hosts either do not initialize gadgets with a descriptor containing the OUT Endpoint completely (like some HP and DELL BIOSes and embedded firmwares like on KVM switches), or initialize them, but will not poll the IN Endpoint.
This patch adds configfs option no_out_endpoint=1 to disable the OUT Endpoint and allows f_hid to receive reports from the host via SETUP/SET_REPORT.
Previously, there was such a feature in f_hid, but it was replaced by the OUT Endpoint [1] in the commit 99c515005857 ("usb: gadget: hidg: register OUT INT endpoint for SET_REPORT"). So this patch actually returns the removed functionality while making it optional. For backward compatibility reasons, the OUT Endpoint mode remains the default behaviour.
- The OUT Endpoint mode provides the report queue and reduces USB overhead (eliminating SETUP routine) on transmitting a report from the host.
- If the SETUP/SET_REPORT mode is used, there is no report queue, so the userspace will only read last report. For classic HID devices like keyboards this is not a problem, since it's intended to transmit the status of the LEDs and only the last report is important. This mode provides better compatibility with strange and buggy host drivers.
Both modes passed USBCV tests. Checking with the USB protocol analyzer also confirmed that everything is working as it should and the new mode ensures operability in all of the described cases.
Link: https://www.spinics.net/lists/linux-usb/msg65494.html [1] Reviewed-by: Maciej Żenczykowski zenczykowski@gmail.com Acked-by: Felipe Balbi balbi@kernel.org Signed-off-by: Maxim Devaev mdevaev@gmail.com Link: https://lore.kernel.org/r/20210821134004.363217-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Stable-dep-of: 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/f_hid.c | 220 +++++++++++++++++++++++----- drivers/usb/gadget/function/u_hid.h | 1 + 2 files changed, 188 insertions(+), 33 deletions(-)
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index 1d10d29c115b..0c200f152036 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -45,12 +45,25 @@ struct f_hidg { unsigned short report_desc_length; char *report_desc; unsigned short report_length; + /* + * use_out_ep - if true, the OUT Endpoint (interrupt out method) + * will be used to receive reports from the host + * using functions with the "intout" suffix. + * Otherwise, the OUT Endpoint will not be configured + * and the SETUP/SET_REPORT method ("ssreport" suffix) + * will be used to receive reports. + */ + bool use_out_ep;
/* recv report */ - struct list_head completed_out_req; spinlock_t read_spinlock; wait_queue_head_t read_queue; + /* recv report - interrupt out only (use_out_ep == 1) */ + struct list_head completed_out_req; unsigned int qlen; + /* recv report - setup set_report only (use_out_ep == 0) */ + char *set_report_buf; + unsigned int set_report_length;
/* send report */ spinlock_t write_spinlock; @@ -79,7 +92,7 @@ static struct usb_interface_descriptor hidg_interface_desc = { .bDescriptorType = USB_DT_INTERFACE, /* .bInterfaceNumber = DYNAMIC */ .bAlternateSetting = 0, - .bNumEndpoints = 2, + /* .bNumEndpoints = DYNAMIC (depends on use_out_ep) */ .bInterfaceClass = USB_CLASS_HID, /* .bInterfaceSubClass = DYNAMIC */ /* .bInterfaceProtocol = DYNAMIC */ @@ -140,7 +153,7 @@ static struct usb_ss_ep_comp_descriptor hidg_ss_out_comp_desc = { /* .wBytesPerInterval = DYNAMIC */ };
-static struct usb_descriptor_header *hidg_ss_descriptors[] = { +static struct usb_descriptor_header *hidg_ss_descriptors_intout[] = { (struct usb_descriptor_header *)&hidg_interface_desc, (struct usb_descriptor_header *)&hidg_desc, (struct usb_descriptor_header *)&hidg_ss_in_ep_desc, @@ -150,6 +163,14 @@ static struct usb_descriptor_header *hidg_ss_descriptors[] = { NULL, };
+static struct usb_descriptor_header *hidg_ss_descriptors_ssreport[] = { + (struct usb_descriptor_header *)&hidg_interface_desc, + (struct usb_descriptor_header *)&hidg_desc, + (struct usb_descriptor_header *)&hidg_ss_in_ep_desc, + (struct usb_descriptor_header *)&hidg_ss_in_comp_desc, + NULL, +}; + /* High-Speed Support */
static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = { @@ -176,7 +197,7 @@ static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = { */ };
-static struct usb_descriptor_header *hidg_hs_descriptors[] = { +static struct usb_descriptor_header *hidg_hs_descriptors_intout[] = { (struct usb_descriptor_header *)&hidg_interface_desc, (struct usb_descriptor_header *)&hidg_desc, (struct usb_descriptor_header *)&hidg_hs_in_ep_desc, @@ -184,6 +205,13 @@ static struct usb_descriptor_header *hidg_hs_descriptors[] = { NULL, };
+static struct usb_descriptor_header *hidg_hs_descriptors_ssreport[] = { + (struct usb_descriptor_header *)&hidg_interface_desc, + (struct usb_descriptor_header *)&hidg_desc, + (struct usb_descriptor_header *)&hidg_hs_in_ep_desc, + NULL, +}; + /* Full-Speed Support */
static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = { @@ -210,7 +238,7 @@ static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = { */ };
-static struct usb_descriptor_header *hidg_fs_descriptors[] = { +static struct usb_descriptor_header *hidg_fs_descriptors_intout[] = { (struct usb_descriptor_header *)&hidg_interface_desc, (struct usb_descriptor_header *)&hidg_desc, (struct usb_descriptor_header *)&hidg_fs_in_ep_desc, @@ -218,6 +246,13 @@ static struct usb_descriptor_header *hidg_fs_descriptors[] = { NULL, };
+static struct usb_descriptor_header *hidg_fs_descriptors_ssreport[] = { + (struct usb_descriptor_header *)&hidg_interface_desc, + (struct usb_descriptor_header *)&hidg_desc, + (struct usb_descriptor_header *)&hidg_fs_in_ep_desc, + NULL, +}; + /*-------------------------------------------------------------------------*/ /* Strings */
@@ -241,8 +276,8 @@ static struct usb_gadget_strings *ct_func_strings[] = { /*-------------------------------------------------------------------------*/ /* Char Device */
-static ssize_t f_hidg_read(struct file *file, char __user *buffer, - size_t count, loff_t *ptr) +static ssize_t f_hidg_intout_read(struct file *file, char __user *buffer, + size_t count, loff_t *ptr) { struct f_hidg *hidg = file->private_data; struct f_hidg_req_list *list; @@ -258,15 +293,15 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
spin_lock_irqsave(&hidg->read_spinlock, flags);
-#define READ_COND (!list_empty(&hidg->completed_out_req)) +#define READ_COND_INTOUT (!list_empty(&hidg->completed_out_req))
/* wait for at least one buffer to complete */ - while (!READ_COND) { + while (!READ_COND_INTOUT) { spin_unlock_irqrestore(&hidg->read_spinlock, flags); if (file->f_flags & O_NONBLOCK) return -EAGAIN;
- if (wait_event_interruptible(hidg->read_queue, READ_COND)) + if (wait_event_interruptible(hidg->read_queue, READ_COND_INTOUT)) return -ERESTARTSYS;
spin_lock_irqsave(&hidg->read_spinlock, flags); @@ -316,6 +351,60 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer, return count; }
+#define READ_COND_SSREPORT (hidg->set_report_buf != NULL) + +static ssize_t f_hidg_ssreport_read(struct file *file, char __user *buffer, + size_t count, loff_t *ptr) +{ + struct f_hidg *hidg = file->private_data; + char *tmp_buf = NULL; + unsigned long flags; + + if (!count) + return 0; + + spin_lock_irqsave(&hidg->read_spinlock, flags); + + while (!READ_COND_SSREPORT) { + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + if (wait_event_interruptible(hidg->read_queue, READ_COND_SSREPORT)) + return -ERESTARTSYS; + + spin_lock_irqsave(&hidg->read_spinlock, flags); + } + + count = min_t(unsigned int, count, hidg->set_report_length); + tmp_buf = hidg->set_report_buf; + hidg->set_report_buf = NULL; + + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + + if (tmp_buf != NULL) { + count -= copy_to_user(buffer, tmp_buf, count); + kfree(tmp_buf); + } else { + count = -ENOMEM; + } + + wake_up(&hidg->read_queue); + + return count; +} + +static ssize_t f_hidg_read(struct file *file, char __user *buffer, + size_t count, loff_t *ptr) +{ + struct f_hidg *hidg = file->private_data; + + if (hidg->use_out_ep) + return f_hidg_intout_read(file, buffer, count, ptr); + else + return f_hidg_ssreport_read(file, buffer, count, ptr); +} + static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req) { struct f_hidg *hidg = (struct f_hidg *)ep->driver_data; @@ -439,14 +528,20 @@ static __poll_t f_hidg_poll(struct file *file, poll_table *wait) if (WRITE_COND) ret |= EPOLLOUT | EPOLLWRNORM;
- if (READ_COND) - ret |= EPOLLIN | EPOLLRDNORM; + if (hidg->use_out_ep) { + if (READ_COND_INTOUT) + ret |= EPOLLIN | EPOLLRDNORM; + } else { + if (READ_COND_SSREPORT) + ret |= EPOLLIN | EPOLLRDNORM; + }
return ret; }
#undef WRITE_COND -#undef READ_COND +#undef READ_COND_SSREPORT +#undef READ_COND_INTOUT
static int f_hidg_release(struct inode *inode, struct file *fd) { @@ -473,7 +568,7 @@ static inline struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep, return alloc_ep_req(ep, length); }
-static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req) +static void hidg_intout_complete(struct usb_ep *ep, struct usb_request *req) { struct f_hidg *hidg = (struct f_hidg *) req->context; struct usb_composite_dev *cdev = hidg->func.config->cdev; @@ -508,6 +603,37 @@ static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req) } }
+static void hidg_ssreport_complete(struct usb_ep *ep, struct usb_request *req) +{ + struct f_hidg *hidg = (struct f_hidg *)req->context; + struct usb_composite_dev *cdev = hidg->func.config->cdev; + char *new_buf = NULL; + unsigned long flags; + + if (req->status != 0 || req->buf == NULL || req->actual == 0) { + ERROR(cdev, + "%s FAILED: status=%d, buf=%p, actual=%d\n", + __func__, req->status, req->buf, req->actual); + return; + } + + spin_lock_irqsave(&hidg->read_spinlock, flags); + + new_buf = krealloc(hidg->set_report_buf, req->actual, GFP_ATOMIC); + if (new_buf == NULL) { + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + return; + } + hidg->set_report_buf = new_buf; + + hidg->set_report_length = req->actual; + memcpy(hidg->set_report_buf, req->buf, req->actual); + + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + + wake_up(&hidg->read_queue); +} + static int hidg_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl) { @@ -555,7 +681,11 @@ static int hidg_setup(struct usb_function *f, case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8 | HID_REQ_SET_REPORT): VDBG(cdev, "set_report | wLength=%d\n", ctrl->wLength); - goto stall; + if (hidg->use_out_ep) + goto stall; + req->complete = hidg_ssreport_complete; + req->context = hidg; + goto respond; break;
case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8 @@ -643,15 +773,18 @@ static void hidg_disable(struct usb_function *f) unsigned long flags;
usb_ep_disable(hidg->in_ep); - usb_ep_disable(hidg->out_ep);
- spin_lock_irqsave(&hidg->read_spinlock, flags); - list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) { - free_ep_req(hidg->out_ep, list->req); - list_del(&list->list); - kfree(list); + if (hidg->out_ep) { + usb_ep_disable(hidg->out_ep); + + spin_lock_irqsave(&hidg->read_spinlock, flags); + list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) { + free_ep_req(hidg->out_ep, list->req); + list_del(&list->list); + kfree(list); + } + spin_unlock_irqrestore(&hidg->read_spinlock, flags); } - spin_unlock_irqrestore(&hidg->read_spinlock, flags);
spin_lock_irqsave(&hidg->write_spinlock, flags); if (!hidg->write_pending) { @@ -697,8 +830,7 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt) } }
- - if (hidg->out_ep != NULL) { + if (hidg->use_out_ep && hidg->out_ep != NULL) { /* restart endpoint */ usb_ep_disable(hidg->out_ep);
@@ -723,7 +855,7 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt) hidg_alloc_ep_req(hidg->out_ep, hidg->report_length); if (req) { - req->complete = hidg_set_report_complete; + req->complete = hidg_intout_complete; req->context = hidg; status = usb_ep_queue(hidg->out_ep, req, GFP_ATOMIC); @@ -749,7 +881,8 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt) } return 0; disable_out_ep: - usb_ep_disable(hidg->out_ep); + if (hidg->out_ep) + usb_ep_disable(hidg->out_ep); free_req_in: if (req_in) free_ep_req(hidg->in_ep, req_in); @@ -801,14 +934,21 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f) goto fail; hidg->in_ep = ep;
- ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc); - if (!ep) - goto fail; - hidg->out_ep = ep; + hidg->out_ep = NULL; + if (hidg->use_out_ep) { + ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc); + if (!ep) + goto fail; + hidg->out_ep = ep; + } + + /* used only if use_out_ep == 1 */ + hidg->set_report_buf = NULL;
/* set descriptor dynamic values */ hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass; hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol; + hidg_interface_desc.bNumEndpoints = hidg->use_out_ep ? 2 : 1; hidg->protocol = HID_REPORT_PROTOCOL; hidg->idle = 1; hidg_ss_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length); @@ -839,9 +979,19 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f) hidg_ss_out_ep_desc.bEndpointAddress = hidg_fs_out_ep_desc.bEndpointAddress;
- status = usb_assign_descriptors(f, hidg_fs_descriptors, - hidg_hs_descriptors, hidg_ss_descriptors, - hidg_ss_descriptors); + if (hidg->use_out_ep) + status = usb_assign_descriptors(f, + hidg_fs_descriptors_intout, + hidg_hs_descriptors_intout, + hidg_ss_descriptors_intout, + hidg_ss_descriptors_intout); + else + status = usb_assign_descriptors(f, + hidg_fs_descriptors_ssreport, + hidg_hs_descriptors_ssreport, + hidg_ss_descriptors_ssreport, + hidg_ss_descriptors_ssreport); + if (status) goto fail;
@@ -956,6 +1106,7 @@ CONFIGFS_ATTR(f_hid_opts_, name)
F_HID_OPT(subclass, 8, 255); F_HID_OPT(protocol, 8, 255); +F_HID_OPT(no_out_endpoint, 8, 1); F_HID_OPT(report_length, 16, 65535);
static ssize_t f_hid_opts_report_desc_show(struct config_item *item, char *page) @@ -1015,6 +1166,7 @@ CONFIGFS_ATTR_RO(f_hid_opts_, dev); static struct configfs_attribute *hid_attrs[] = { &f_hid_opts_attr_subclass, &f_hid_opts_attr_protocol, + &f_hid_opts_attr_no_out_endpoint, &f_hid_opts_attr_report_length, &f_hid_opts_attr_report_desc, &f_hid_opts_attr_dev, @@ -1099,6 +1251,7 @@ static void hidg_free(struct usb_function *f) hidg = func_to_hidg(f); opts = container_of(f->fi, struct f_hid_opts, func_inst); kfree(hidg->report_desc); + kfree(hidg->set_report_buf); kfree(hidg); mutex_lock(&opts->lock); --opts->refcnt; @@ -1145,6 +1298,7 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi) return ERR_PTR(-ENOMEM); } } + hidg->use_out_ep = !opts->no_out_endpoint;
mutex_unlock(&opts->lock);
diff --git a/drivers/usb/gadget/function/u_hid.h b/drivers/usb/gadget/function/u_hid.h index 2f5ca4bfa7ff..c090eb6c9759 100644 --- a/drivers/usb/gadget/function/u_hid.h +++ b/drivers/usb/gadget/function/u_hid.h @@ -20,6 +20,7 @@ struct f_hid_opts { int minor; unsigned char subclass; unsigned char protocol; + unsigned char no_out_endpoint; unsigned short report_length; unsigned short report_desc_length; unsigned char *report_desc;