Re: [PATCH] media: uvcvideo: Factor out usb_string() calls

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 10/25/22 11:47, Laurent Pinchart wrote:
When parsing UVC descriptors to instantiate entity, the driver calls
usb_string() to retrieve the entity name from the device, and falls back
to a default name if the string can't be retrieved. This code pattern
occurs multiple times. Factor it out to a separate helper function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
Ricardo, Guenter, this applies on top of "media: uvcvideo: Handle errors
from calls to usb_string". Any opinion ?

Great cleanup. Looks good to me.

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Guenter

---
  drivers/media/usb/uvc/uvc_driver.c | 59 ++++++++++++++++++------------
  1 file changed, 35 insertions(+), 24 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index bd3716a359b0..6eb011f452e5 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -813,6 +813,27 @@ static struct uvc_entity *uvc_alloc_entity(u16 type, u16 id,
  	return entity;
  }
+static void uvc_entity_set_name(struct uvc_device *dev, struct uvc_entity *entity,
+				const char *type_name, u8 string_id)
+{
+	int ret;
+
+	/*
+	 * First attempt to read the entity name from the device. If the entity
+	 * has no associated string, or if reading the string fails (most
+	 * likely due to a buggy firmware), fall back to default names based on
+	 * the entity type.
+	 */
+	if (string_id) {
+		ret = usb_string(dev->udev, string_id, entity->name,
+				 sizeof(entity->name));
+		if (!ret)
+			return;
+	}
+
+	sprintf(entity->name, "%s %u", type_name, entity->id);
+}
+
  /* Parse vendor-specific extensions. */
  static int uvc_parse_vendor_control(struct uvc_device *dev,
  	const unsigned char *buffer, int buflen)
@@ -879,9 +900,7 @@ static int uvc_parse_vendor_control(struct uvc_device *dev,
  					       + n;
  		memcpy(unit->extension.bmControls, &buffer[23+p], 2*n);
- if (buffer[24+p+2*n] == 0 ||
-		    usb_string(udev, buffer[24+p+2*n], unit->name, sizeof(unit->name)) < 0)
-			sprintf(unit->name, "Extension %u", buffer[3]);
+		uvc_entity_set_name(dev, unit, "Extension", buffer[24+p+2*n]);
list_add_tail(&unit->list, &dev->entities);
  		handled = 1;
@@ -899,6 +918,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
  	struct usb_interface *intf;
  	struct usb_host_interface *alts = dev->intf->cur_altsetting;
  	unsigned int i, n, p, len;
+	const char *type_name;
  	u16 type;
switch (buffer[2]) {
@@ -1004,15 +1024,14 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
  			memcpy(term->media.bmTransportModes, &buffer[10+n], p);
  		}
- if (buffer[7] == 0 ||
-		    usb_string(udev, buffer[7], term->name, sizeof(term->name)) < 0) {
-			if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA)
-				sprintf(term->name, "Camera %u", buffer[3]);
-			if (UVC_ENTITY_TYPE(term) == UVC_ITT_MEDIA_TRANSPORT_INPUT)
-				sprintf(term->name, "Media %u", buffer[3]);
-			else
-				sprintf(term->name, "Input %u", buffer[3]);
-		}
+		if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA)
+			type_name = "Camera";
+		else if (UVC_ENTITY_TYPE(term) == UVC_ITT_MEDIA_TRANSPORT_INPUT)
+			type_name = "Media";
+		else
+			type_name = "Input";
+
+		uvc_entity_set_name(dev, term, type_name, buffer[7]);
list_add_tail(&term->list, &dev->entities);
  		break;
@@ -1045,9 +1064,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(term->baSourceID, &buffer[7], 1); - if (buffer[8] == 0 ||
-		    usb_string(udev, buffer[8], term->name, sizeof(term->name)) < 0)
-			sprintf(term->name, "Output %u", buffer[3]);
+		uvc_entity_set_name(dev, term, "Output", buffer[8]);
list_add_tail(&term->list, &dev->entities);
  		break;
@@ -1068,9 +1085,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(unit->baSourceID, &buffer[5], p); - if (buffer[5+p] == 0 ||
-		    usb_string(udev, buffer[5+p], unit->name, sizeof(unit->name)) < 0)
-			sprintf(unit->name, "Selector %u", buffer[3]);
+		uvc_entity_set_name(dev, unit, "Selector", buffer[5+p]);
list_add_tail(&unit->list, &dev->entities);
  		break;
@@ -1099,9 +1114,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
  		if (dev->uvc_version >= 0x0110)
  			unit->processing.bmVideoStandards = buffer[9+n];
- if (buffer[8+n] == 0 ||
-		    usb_string(udev, buffer[8+n], unit->name, sizeof(unit->name)) < 0)
-			sprintf(unit->name, "Processing %u", buffer[3]);
+		uvc_entity_set_name(dev, unit, "Processing", buffer[8+n]);
list_add_tail(&unit->list, &dev->entities);
  		break;
@@ -1128,9 +1141,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
  		unit->extension.bmControls = (u8 *)unit + sizeof(*unit);
  		memcpy(unit->extension.bmControls, &buffer[23+p], n);
- if (buffer[23+p+n] == 0 ||
-		    usb_string(udev, buffer[23+p+n], unit->name, sizeof(unit->name)) < 0)
-			sprintf(unit->name, "Extension %u", buffer[3]);
+		uvc_entity_set_name(dev, unit, "Extension", buffer[23+p+n]);
list_add_tail(&unit->list, &dev->entities);
  		break;




[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]

  Powered by Linux