V4L/DVB (5517): Usbvision: store the device database more efficiently

One bit wide bitfields need to declared unsigned to have the range 0 to
1, or they have the range -1 to 0.

A few techniques to reduce the driver's size by about 1700 bytes on ia32,
probably more on x86-64.

Put the biggest fields first, less padding is necessary that way.

Put fields with a limited range into a smaller type.  For example
VideoChannels will fit in 3 bits, and TunerType can use 8 bits.

Vin_Reg1, Vin_Reg2, and Dvi_yuv define values for 8-bit registers, but
they can't just go into an 8-bit field with no changes, since -1 was used
as a flag to indicate a value was not present.  So what we do is create a
one-bit flag for each one to indicate if a value is or is not present.

This only takes 9 bits and has the added advantage that when the register
isn't overridden (Vin_Reg[12] never are) it doesn't need to appear in the
structure definition since the default value for the flag will be zero.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Acked-by: Thierry MERLE <thierry.merle@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/media/video/usbvision/usbvision-core.c b/drivers/media/video/usbvision/usbvision-core.c
index f2154dc072e..fee4548a9cc 100644
--- a/drivers/media/video/usbvision/usbvision-core.c
+++ b/drivers/media/video/usbvision/usbvision-core.c
@@ -2040,8 +2040,8 @@ int usbvision_set_input(struct usb_usbvision *usbvision)
 		return 0;
 
 	/* Set input format expected from decoder*/
-	if (usbvision_device_data[usbvision->DevModel].Vin_Reg1 >= 0) {
-		value[0] = usbvision_device_data[usbvision->DevModel].Vin_Reg1 & 0xff;
+	if (usbvision_device_data[usbvision->DevModel].Vin_Reg1_override) {
+		value[0] = usbvision_device_data[usbvision->DevModel].Vin_Reg1;
 	} else if(usbvision_device_data[usbvision->DevModel].Codec == CODEC_SAA7113) {
 		/* SAA7113 uses 8 bit output */
 		value[0] = USBVISION_8_422_SYNC;
@@ -2112,8 +2112,8 @@ int usbvision_set_input(struct usb_usbvision *usbvision)
 
 	dvi_yuv_value = 0x00;	/* U comes after V, Ya comes after U/V, Yb comes after Yb */
 
-	if(usbvision_device_data[usbvision->DevModel].Dvi_yuv >= 0){
-		dvi_yuv_value = usbvision_device_data[usbvision->DevModel].Dvi_yuv & 0xff;
+	if(usbvision_device_data[usbvision->DevModel].Dvi_yuv_override){
+		dvi_yuv_value = usbvision_device_data[usbvision->DevModel].Dvi_yuv;
 	}
 	else if(usbvision_device_data[usbvision->DevModel].Codec == CODEC_SAA7113) {
 	/* This changes as the fine sync control changes. Further investigation necessary */