[PATCH] brcmfmac: Make sure CLM downloading is optional

[PATCH] brcmfmac: Make sure CLM downloading is optional

[Bjorn Andersson]

The presence of a CLM file is described as optional, but missing the clm
blob causes the preinit to return unsuccessfully. Fix this by ignoring
the return value of the brcmf_c_process_clm_blob().

Also remove the extra debug print, as brcmf_c_process_clm_blob() already
did print a useful error message before returning.

Fixes: fdd0bd88ceae ("brcmfmac: add CLM download support")
Cc: stable@vger.kernel.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

This regression was introduced in v4.15-rc1, but I unfortunately didn't test
WiFi until now. Included a Cc to stable@ in case you choose to pick this up
after v4.15.

 drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
index 6a59d0609d30..0c67ba6ae135 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
@@ -278,12 +278,8 @@ int brcmf_c_preinit_dcmds(struct brcmf_if *ifp)
 	}
 	ri->result = err;
 
-	/* Do any CLM downloading */
-	err = brcmf_c_process_clm_blob(ifp);
-	if (err < 0) {
-		brcmf_err("download CLM blob file failed, %d\n", err);
-		goto done;
-	}
+	/* Do any optional CLM downloading */
+	brcmf_c_process_clm_blob(ifp);
 
 	/* query for 'ver' to get version info from firmware */
 	memset(buf, 0, sizeof(buf));
-- 
2.15.0

Re: [PATCH] brcmfmac: Make sure CLM downloading is optional

[Arend van Spriel]

On 1/15/2018 6:10 PM, Bjorn Andersson wrote:
> The presence of a CLM file is described as optional, but missing the clm
> blob causes the preinit to return unsuccessfully. Fix this by ignoring
> the return value of the brcmf_c_process_clm_blob().
>
> Also remove the extra debug print, as brcmf_c_process_clm_blob() already
> did print a useful error message before returning.
>
> Fixes: fdd0bd88ceae ("brcmfmac: add CLM download support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>
> This regression was introduced in v4.15-rc1, but I unfortunately didn't test
> WiFi until now. Included a Cc to stable@ in case you choose to pick this up
> after v4.15.

Hi Bjorn,

Thanks for looking into this. Actually there already have been a couple 
of fixes posted on the linux-wireless list. [1] was rejected, [2] is 
being discussed, and [2] was posted by me and I was awaiting response 
from the guy reporting it.

Now the thing is that for old (Broadcom) firmware this is optional. 
Those firmwares don't even have CLM support and those that do have the 
CLM data embedded in firmware. However, Cypress wants to provide their 
customers with firmware without CLM data. For those devices it is not 
optional. I still prefer we add a mechanism to the driver to detect 
that, but we do not have that yet.

Now regarding your patch some comments below ...

>   drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c | 8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
> index 6a59d0609d30..0c67ba6ae135 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
> @@ -278,12 +278,8 @@ int brcmf_c_preinit_dcmds(struct brcmf_if *ifp)
>   	}
>   	ri->result = err;
>
> -	/* Do any CLM downloading */
> -	err = brcmf_c_process_clm_blob(ifp);
> -	if (err < 0) {
> -		brcmf_err("download CLM blob file failed, %d\n", err);
> -		goto done;
> -	}
> +	/* Do any optional CLM downloading */
> +	brcmf_c_process_clm_blob(ifp);

The error print is indeed redundant and should be removed here. However, 
brcmf_c_process_clm_blob() also returns -ENOMEM upon allocation failure 
and I would still fail the driver probe for that.

Regards,
Arend

[1] https://patchwork.kernel.org/patch/10106571/
[2] https://patchwork.kernel.org/patch/10159731/
[3] https://patchwork.kernel.org/patch/10154595/

Re: [PATCH] brcmfmac: Make sure CLM downloading is optional

[Bjorn Andersson]

On Mon 15 Jan 11:40 PST 2018, Arend van Spriel wrote:

> On 1/15/2018 6:10 PM, Bjorn Andersson wrote:
> > The presence of a CLM file is described as optional, but missing the clm
> > blob causes the preinit to return unsuccessfully. Fix this by ignoring
> > the return value of the brcmf_c_process_clm_blob().
> > 
> > Also remove the extra debug print, as brcmf_c_process_clm_blob() already
> > did print a useful error message before returning.
> > 
> > Fixes: fdd0bd88ceae ("brcmfmac: add CLM download support")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > ---
> > 
> > This regression was introduced in v4.15-rc1, but I unfortunately didn't test
> > WiFi until now. Included a Cc to stable@ in case you choose to pick this up
> > after v4.15.
> 
> Hi Bjorn,
> 
> Thanks for looking into this. Actually there already have been a couple of
> fixes posted on the linux-wireless list. [1] was rejected, [2] is being
> discussed, and [2] was posted by me and I was awaiting response from the guy
> reporting it.
> 

Thanks for pointing me to these discussions, I did for some reason not
find them this morning. I don't see the need for the retry in [1], so I
think that's invalid.

I tested [2] and it works well for me, but I agree with Kalle that a
better description of why would be in order. Unfortunatley I can't find
it in my inbox...even though I'm subscribed to linux-wireless@.

The answer to Kalle's question should probably include a reference to
0542ad88fbdd ("firmware loader: Fix _request_firmware_load() return val
for fw load abort")

> Now the thing is that for old (Broadcom) firmware this is optional. Those
> firmwares don't even have CLM support and those that do have the CLM data
> embedded in firmware.

I don't know which applies to my device, but it at least doesn't come
with a dedicated clm blob - and the device won't receive any upgrades
and hence will never get a clm blob.

> However, Cypress wants to provide their customers with
> firmware without CLM data. For those devices it is not optional. I still
> prefer we add a mechanism to the driver to detect that, but we do not have
> that yet.
> 

That sounds reasonable, but I hope we can sort out the regression first
and then add such logic.

> Now regarding your patch some comments below ...
> 
> >   drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c | 8 ++------
> >   1 file changed, 2 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
> > index 6a59d0609d30..0c67ba6ae135 100644
> > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
> > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
> > @@ -278,12 +278,8 @@ int brcmf_c_preinit_dcmds(struct brcmf_if *ifp)
> >   	}
> >   	ri->result = err;
> > 
> > -	/* Do any CLM downloading */
> > -	err = brcmf_c_process_clm_blob(ifp);
> > -	if (err < 0) {
> > -		brcmf_err("download CLM blob file failed, %d\n", err);
> > -		goto done;
> > -	}
> > +	/* Do any optional CLM downloading */
> > +	brcmf_c_process_clm_blob(ifp);
> 
> The error print is indeed redundant and should be removed here. However,
> brcmf_c_process_clm_blob() also returns -ENOMEM upon allocation failure and
> I would still fail the driver probe for that.
> 

Agreed, but as we want to let a few errors, specifically from the
firmware loader, slip by I believe it's better to check the return value
there instead. So I prefer Write's [2].

Regards,
Bjorn