[drm:radeon_dp_i2c_aux_ch] *ERROR* aux i2c too many retries, giving up

[drm:radeon_dp_i2c_aux_ch] *ERROR* aux i2c too many retries, giving up

[Andrew Benton]

Hello,

Please cc me in any replies as I'm not subscribed.

When booting a 3.1.0-rc10 kernel, right at the start I get an error
message printed to the screen:

[drm:radeon_dp_i2c_aux_ch] *ERROR* aux i2c too many retries, giving up

It's a quad core computer and it prints it 4 times. On another computer
which is a dual core it prints the message twice. Both computers have
Radeon graphics cards which need firmware compiled into the kernel to
work. This computer uses BARTS_mc.bin, BARTS_me.bin, BARTS_pfp.bin and
BTC_rlc.bin. The kitchen computer uses REDWOOD_rlc.bin, REDWOOD_pfp.bin
and REDWOOD_me.bin. Both computers seem to be working fine as far as I
can see. Is this error message something to be concerned about? I
thought the radeon driver uses i2c to enable sensors to report the
temperature of the card, but that seems to be working fine. I boot with
the quite command line argument and it gets rid of most kernel output,
but not these error messages. Is there some way I can get rid of these
alarming messages? Some kernel option that will make them just complain
to the kernel log? Or is there some option I should enable to keep the
radeon i2c whatever it is happy?

Andy

[drm:radeon_dp_i2c_aux_ch] *ERROR* aux i2c too many retries, giving up

[Andrew Benton]

Hello

When I boot up my computer with a 3.1 kernel I get a scary error
message just bellow the penguins:

[drm:radeon_dp_i2c_aux_ch] *ERROR* aux i2c too many retries, giving up

On a dual core it's printed twice, on a quad core it's printed 4 times.
I compile my kernels without modules and with the Radeon firmware
compiled into the kernel. As far as I can see the computers are working
perfectly but I'd like to understand this error message. It seems a bit
strange that it's printed to the screen even if I boot the kernel with
the quiet command line option. If someone could tell me what the error
message means I would be grateful (please CC me as I'm not subscribed).

I emailed this list asking about this last Wednesday but got no replies
so I've had to simply fall back on removing this kernel "feature":

sed -i 's#\tDRM_ERROR("aux i2c#//&#' \
  drivers/gpu/drm/radeon/atombios_dp.c

This makes the error message go away but it's not ideal, I'd rather
understand what it means.

Andy