| Message ID | CACRpkdYLkKmy_pSizrSvE3x1qpGBUY=djLY0AAyt9CqOzdOoVg@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
Hi Linus, On 11/08/14 13:49, Linus Walleye wrote: > On Mon, Aug 11, 2014 at 1:42 PM, Linus Walleij <linus.walleij@linaro.org> wrote: >> On Mon, Aug 11, 2014 at 1:21 PM, Linus Walleij <linus.walleij@linaro.org> wrote: >> >>> The symptom is that not even earlyprints come up if I put some >>> printascii() in start_kernel. >> >> Bah that was me not realizing that the defaults for DEBUG_UART_PHYS >> and DEBUG_UART_VIRT has to be set up properly... now I get the >> earlyprints. >> >> It seems to hang in the gsbi driver probe, off to debug. > > It appears that this oneliner gets the kernel booting again: > > diff --git a/drivers/soc/qcom/qcom_gsbi.c b/drivers/soc/qcom/qcom_gsbi.c > index 447458e696a9..1759a3c9140a 100644 > --- a/drivers/soc/qcom/qcom_gsbi.c > +++ b/drivers/soc/qcom/qcom_gsbi.c > @@ -57,7 +57,7 @@ static int gsbi_probe(struct platform_device *pdev) > /* make sure the gsbi control write is not reordered */ > wmb(); > > - clk_disable_unprepare(hclk); > + //clk_disable_unprepare(hclk); > > return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); > } > > The kernel hangs during disable/unprepare of the hclk for the GSBI. > Turning off hclk's could be dangerous if there are vital system > components using the hclk which does not yet have a reference > taken in the kernel, due to missing drivers or similar. > There is a patch to fix this http://www.spinics.net/lists/linux-arm-msm/msg09633.html > Any ideas? IMO, hclk is also used by the serial IP, disabling the clock while its being used by early printk would result in hang, I think that's what you are seeing. --srini > > Yours, > Linus Walleij > -- > To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Aug 11, 2014 at 6:35 PM, Srinivas Kandagatla <srinivas.kandagatla@linaro.org> wrote: > On 11/08/14 13:49, Linus Walleye wrote: Hey! :-) >> The kernel hangs during disable/unprepare of the hclk for the GSBI. >> Turning off hclk's could be dangerous if there are vital system >> components using the hclk which does not yet have a reference >> taken in the kernel, due to missing drivers or similar. > > There is a patch to fix this > http://www.spinics.net/lists/linux-arm-msm/msg09633.html Awesome, fixes the issue for me, Tested-by: Linus Walleij <linus.walleij@linaro.org> Please funnel this as a fix for kernels v3.16+ Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/soc/qcom/qcom_gsbi.c b/drivers/soc/qcom/qcom_gsbi.c index 447458e696a9..1759a3c9140a 100644 --- a/drivers/soc/qcom/qcom_gsbi.c +++ b/drivers/soc/qcom/qcom_gsbi.c @@ -57,7 +57,7 @@ static int gsbi_probe(struct platform_device *pdev) /* make sure the gsbi control write is not reordered */ wmb(); - clk_disable_unprepare(hclk); + //clk_disable_unprepare(hclk); return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); }