diff options
author | Trent Piepho <xyzzy@speakeasy.org> | 2007-04-14 15:16:26 -0300 |
---|---|---|
committer | Mauro Carvalho Chehab <mchehab@infradead.org> | 2007-04-27 15:45:34 -0300 |
commit | c682b3a7fb8ec69ac73511bbb6a378e40aa35f35 (patch) | |
tree | 443ac5b210222822c3f4883964defd2404601d7a /drivers/media/video/usbvision/usbvision.h | |
parent | f7ca6256bc1db4fb44adda99e082f8c80ada8957 (diff) |
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>
Diffstat (limited to 'drivers/media/video/usbvision/usbvision.h')
-rw-r--r-- | drivers/media/video/usbvision/usbvision.h | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/drivers/media/video/usbvision/usbvision.h b/drivers/media/video/usbvision/usbvision.h index b4412a5014a..9cad7773340 100644 --- a/drivers/media/video/usbvision/usbvision.h +++ b/drivers/media/video/usbvision/usbvision.h @@ -342,21 +342,24 @@ struct usbvision_frame { #define BRIDGE_NT1005 1005 struct usbvision_device_data_st { - int Interface; /* to handle special interface number like BELKIN and Hauppauge WinTV-USB II */ - int Codec; - int VideoChannels; __u64 VideoNorm; - int AudioChannels; - int Radio:1; - int vbi:1; - int Tuner:1; - int TunerType; - int Vin_Reg1; - int Vin_Reg2; - int X_Offset; - int Y_Offset; - int Dvi_yuv; - char *ModelString; + const char *ModelString; + int Interface; /* to handle special interface number like BELKIN and Hauppauge WinTV-USB II */ + __u16 Codec; + unsigned VideoChannels:3; + unsigned AudioChannels:2; + unsigned Radio:1; + unsigned vbi:1; + unsigned Tuner:1; + unsigned Vin_Reg1_override:1; /* Override default value with */ + unsigned Vin_Reg2_override:1; /* Vin_Reg1, Vin_Reg2, etc. */ + unsigned Dvi_yuv_override:1; + __u8 Vin_Reg1; + __u8 Vin_Reg2; + __u8 Dvi_yuv; + __u8 TunerType; + __s16 X_Offset; + __s16 Y_Offset; }; /* Declared on usbvision-cards.c */ |