Re: [PATCH 1/2] ASoC: Intel: sst: Fallback to BYT-CR if IRQ 5 is missing

Pierre-Louis Bossart
2018-12-31T15:38:25Z

On 12/22/18 8:47 AM, Stephan Gerhold wrote:
> Some devices detected as BYT-T by the PMIC-type based detection
> have only a single IRQ listed in the 80860F28 ACPI device. This
> causes -ENXIO later when attempting to get the IRQ at index 5.
> It turns out these devices behave more like BYT-CR devices,
> and using the IRQ at index 0 makes sound work correctly.
>
> This patch adds a fallback for these devices to is_byt_cr():
> If there is no IRQ resource at index 5, treating the device
> as BYT-T is guaranteed to fail later, so we can safely treat
> these devices as BYT-CR without breaking any working device.
>
> Link: http://mailman.alsa-project.org/pipermail/alsa-devel/2018-December/143176.html
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> ---
> Moved the "Detected Baytrail-CR platform" message to is_byt_cr()
> so we can log a different message if the fallback is used.
>
> Tested this on my device as-is, and simulated a "normal"
> BYT-T and BYT-CR device (copied their IRQs to a custom DSDT).
>
> sound/soc/intel/atom/sst/sst_acpi.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/intel/atom/sst/sst_acpi.c b/sound/soc/intel/atom/sst/sst_acpi.c
> index 3a95ebbfc45d..755a396121ff 100644
> --- a/sound/soc/intel/atom/sst/sst_acpi.c
> +++ b/sound/soc/intel/atom/sst/sst_acpi.c
> @@ -255,10 +255,22 @@ static int is_byt(void)
> return status;
> }
>
> -static int is_byt_cr(struct device *dev, bool *bytcr)
> +static int is_byt_cr(struct platform_device *pdev, bool *bytcr)
> {
> + struct device *dev = &pdev->dev;
> int status = 0;
>
> + if (platform_get_resource(pdev, IORESOURCE_IRQ, 5) == NULL) {
> + /*
> + * Some devices detected as BYT-T have only a single IRQ listed,
> + * causing platform_get_irq with index 5 to return -ENXIO.
> + * The correct IRQ in this case is at index 0, as used on BYT-CR.
> + */
> + dev_info(dev, "Falling back to Baytrail-CR platform\n");
> + *bytcr = true;
> + return status;
> + }
> +

Isn't this going to bypass the PMIC-based detection on all BYT-CR
devices? Maybe move this code as a fallback used when the PMIC-based
detection isn't positive?

> if (IS_ENABLED(CONFIG_IOSF_MBI)) {
> u32 bios_status;
>
> @@ -278,10 +290,12 @@ static int is_byt_cr(struct device *dev, bool *bytcr)
> /* bits 26:27 mirror PMIC options */
> bios_status = (bios_status >> 26) & 3;
>
> - if ((bios_status == 1) || (bios_status == 3))
> + if ((bios_status == 1) || (bios_status == 3)) {
> + dev_info(dev, "Detected Baytrail-CR platform\n");
> *bytcr = true;
> - else
> + } else {
> dev_info(dev, "BYT-CR not detected\n");
> + }
> }
> } else {
> dev_info(dev, "IOSF_MBI not enabled, no BYT-CR detection\n");
> @@ -333,10 +347,8 @@ static int sst_acpi_probe(struct platform_device *pdev)
> if (ret < 0)
> return ret;
>
> - ret = is_byt_cr(dev, &bytcr);
> + ret = is_byt_cr(pdev, &bytcr);
> if (!(ret < 0 || !bytcr)) {
> - dev_info(dev, "Detected Baytrail-CR platform\n");
> -
> /* override resource info */
> byt_rvp_platform_data.res_info = &bytcr_res_info;
> }