ACK/cmnt: [VIVID][SRU][PATCH] UBUNTU: SAUCE: dma: dw_dmac: Workaround for stop probing on HP X360 laptop v2

[Stefan Bader]

On 16.10.2015 10:18, Phidias Chiang wrote:
> BugLink: http://bugs.launchpad.net/bugs/1501580
> 
> On HP X360, dw_dmac causes random hang when booting, and fail to
> power off when shuting down. The fix from upstream hasn't hit mainline
> yet, but there are already users had the issue. To avoid this problem,
> this workaround return -ENODEV directly when probing if DMI string match
> the product name.
> 
> Signed-off-by: Phidias Chiang <phidias.chiang at canonical.com>
> Reviewed-by: Wen-chien Jesse Sung <jesse.sung at canonical.com>
> 
> ---
>  drivers/dma/dw/platform.c |   14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
> index 272f01f..599df58 100644
> --- a/drivers/dma/dw/platform.c
> +++ b/drivers/dma/dw/platform.c
> @@ -23,6 +23,7 @@
>  #include <linux/of_dma.h>
>  #include <linux/acpi.h>
>  #include <linux/acpi_dma.h>
> +#include <linux/dmi.h>
>  
>  #include "internal.h"
>  
> @@ -158,6 +159,19 @@ static int dw_probe(struct platform_device *pdev)
>  	struct dw_dma_platform_data *pdata;
>  	int err;
>  
> +	/*
> +	* On a certain platform, loading dw_dmac causes issues
> +	* when booting and shuting down. To avoid this problem,
> +	* we temporarily skip the probing process, and will revert
> +	* this workaround when the fix is ready from upstream.
> +	*
> +	* Ref: https://bugzilla.kernel.org/show_bug.cgi?id=101271
> +	*/
> +	if (dmi_match(DMI_PRODUCT_NAME, "HP x360 310 G2 PC")) {
> +		pr_info("HP X360 detected, skip probing dw_dmac\n");
> +		return -ENODEV;
> +	}
> +
>  	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
>  	if (!chip)
>  		return -ENOMEM;
> 

Sounds acceptable with the explanation given. Just wondering whether Vivid is
the only Release affected. What about Wily and Trusty for example...

-Stefan


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: OpenPGP digital signature
URL: <https://lists.ubuntu.com/archives/kernel-team/attachments/20151016/80539818/attachment.sig>