[linux-dvb] SAA7146 short delay flag and budget cards

Gregoire Favre gregoire.favre at gmail.com
Fri Sep 23 22:00:21 CEST 2005


Hello,

first of all, sorry for breaking the thread : I did erase this email and
a friend asked me if I have tested it, so he sends it me back...

I just wanted to report that this patch also improve things here :-)

> Good morning. After moving to an AMD64 system and kernel 2.6.14rc1,
> plus last Saturday's CVS dvb drivers, I found that, while talking with
> my hauppauge DVB-S budget card, delays for frontend IOCTL's
> (FE_READ_STATUS, FE_READ_SNR and FE_READ_SIGNAL_STRENGTH) were
> unexpectedly increased. Each ioctl took 200-400 milliseconds to
> return. After a long and painful search, I found out that the delay
> happened in I2C comms. I noticed that, in av7110.c, a flag was set,
> called SAA7146_I2C_SHORT_DELAY, in the saa7146_extension
> structure. So, I applied the following simple patch:
> 
> --- budget.c~   2005-09-04 14:58:21.000000000 +0200
> +++ budget.c    2005-09-17 23:28:14.000000000 +0200
> @@ -740,7 +740,7 @@
> 
>  static struct saa7146_extension budget_extension = {
>         .name           = "budget dvb\0",
> -       .flags          = 0,
> +       .flags          = SAA7146_I2C_SHORT_DELAY,
> 
>         .module         = THIS_MODULE,
>         .pci_tbl        = pci_tbl,
> 
> Well, the card now reacts *very* quickly, and I do not notice any side
> effects. 
> 
> Is there any reason why this flag is not set?
> 
> Carlo
-- 
	Gr/'egoire FAVRE



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