Re: [PATCH] V4L/DVB: budget-av: wait longer for frontend to power on

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Bjørn Mork wrote:
> Some devices need much more time than 100ms to power on, leading to a
> failure to enable the frontend on the first attempt. Instead we get
> 
> [   38.194200] saa7146: register extension 'budget_av'.
> [   38.253828] budget_av 0000:05:01.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
> [   38.601572] saa7146: found saa7146 @ mem ffffc90000c6ac00 (revision 1, irq 17) (0x1894,0x0022).
> [   39.251324] saa7146 (0): dma buffer size 1347584
> [   39.306757] DVB: registering new adapter (KNC1 DVB-C MK3)
> [   39.462785] adapter failed MAC signature check
> [   39.516159] encoded MAC from EEPROM was ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff
> [   39.892397] KNC1-0: MAC addr = 00:09:d6:6d:94:5c
> [   40.552028] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.580044] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.608026] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.636027] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.652026] DVB: TDA10023(-1): tda10023_writereg, writereg error (reg == 0x00, val == 0x33, ret == -5)
> [   40.664027] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.692027] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.720027] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.748027] saa7146 (0) saa7146_i2c_writeout [irq]: timed out waiting for end of xfer
> [   40.764025] DVB: TDA10023(-1): tda10023_readreg: readreg error (reg == 0x1a, ret == -5)
> [   40.764067] budget-av: A frontend driver was not found for device [1131:7146] subsystem [1894:0022]
> 
> Unloading and the reloading the driver will work around this problem.  But
> it can also be easily fixed by increasing the wait period after powering
> on.  The optimum value is unclear to me.  But I've found the 500 ms is not
> enough.  5 s is enough for my card, but might be more than actually needed.
> However, as long as we don't handle this failure more gracefully, then the
> timeout need to be long enough.
> 
> Signed-off-by: Bjørn Mork <bjorn@mork.no>
> Cc: stable@kernel.org
> ---
> Hello,
> 
> I have recently bought a KNC1 clone, called Mystique CaBiX-C2.  This card 
> would just not work on reboot in my system, giving the errors shown above.
> Unloading the module and then loading it again always fixed the problem,
> indicating that it was just a startup timing problem.
> 
> As you can see, the i2c timeouts are from the frontend attach function, 
> tda10023_attach():
> 	/* wakeup if in standby */
> 	tda10023_writereg (state, 0x00, 0x33);
> 	/* check if the demod is there */
> 	if ((tda10023_readreg(state, 0x1a) & 0xf0) != 0x70) goto error;
> 
> cleary showing that it just isn't responding yet at that point.
> 
> I first tried increasing the msleep() to 500 ms, but still got the same
> error.  Increasing it to 5000 ms helped, however, and made my card work
> from boot.  I have not tried any values inbetween, as each attempt AFAIK
> requires a reboot to get the card into the "cold state" where it will
> fail.
> 
> dmesg with the patch installed:
> 
> [   37.786955] saa7146: register extension 'budget_av'.
> [   37.846592] budget_av 0000:05:01.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
> [   37.933318] saa7146: found saa7146 @ mem ffffc90000c70c00 (revision 1, irq 17) (0x1894,0x0022).
> [   38.037851] saa7146 (0): dma buffer size 1347584
> [   38.093224] DVB: registering new adapter (KNC1 DVB-C MK3)
> [   38.194254] adapter failed MAC signature check
> [   38.247527] encoded MAC from EEPROM was ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff:ff
> [   38.622678] KNC1-0: MAC addr = 00:09:d6:6d:94:5c
> [   43.765897] DVB: registering adapter 0 frontend 0 (Philips TDA10023 DVB-C)...
> [   43.851587] budget-av: ci interface initialised.
> 
> Please consider this patch.  Or maybe it is possible to wait smarter,
> testing actual frontend power status instead of just a blind sleep?
> 
> I've also included a CC stable as I've had the same problem with the 2.6.32
> and 2.6.33 stable drivers.

Are you sure you really need 5 seconds to initialize? This time is probably
board-specific, and shouldn't be applied as-is. So, if you really need such
high timeout, it should be added inside the switch.

I dunno if is there a way to test if the power-on cycle has completed,
but for sure an approach like that would be better than blindly waiting
for 5 secs.

> 
> 
> Bjørn
> 
>  drivers/media/dvb/ttpci/budget-av.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/dvb/ttpci/budget-av.c b/drivers/media/dvb/ttpci/budget-av.c
> index 983672a..b53bd80 100644
> --- a/drivers/media/dvb/ttpci/budget-av.c
> +++ b/drivers/media/dvb/ttpci/budget-av.c
> @@ -1215,7 +1215,7 @@ static void frontend_init(struct budget_av *budget_av)
>  	saa7146_setgpio(saa, 0, SAA7146_GPIO_OUTLO);
>  
>  	/* Wait for PowerON */
> -	msleep(100);
> +	msleep(5000);
>  
>  	/* additional setup necessary for the PLUS cards */
>  	switch (saa->pci->subsystem_device) {


-- 

Cheers,
Mauro