On 12/16/18 12:54 PM, Stephan Gerhold wrote:
Hi,
I have an Intel Bay Trail (BYT-T) tablet that was originally shipped with Android. With the right quirks, bytcr-rt5640 is working fine, but there is a problem in sst_acpi.c that is preventing it from working with a mainline kernel:
Even though this is a BYT-T device, there is no IRQ at index 5 in the ACPI DSDT table. This means that SST will fail to probe, and actually leads to a NULL pointer dereference later when the ALSA device is first opened. (I have submitted a possible solution for this as "[PATCH] ASoC: Intel: sst: Delay machine device creation until after initialization")
The correct IRQ is actually located on index 0, just like it is already being used for BYT-CR devices. So if I force is_byt_cr() to return TRUE, everything works as expected.
So the root cause of your problem is that the detection of byt-cr doesn't work? That would be a first.
Can you please double-check that CONFIG_IOSF_MBI is enabled and provide a trace of the bios status in this piece of code:
/* bits 26:27 mirror PMIC options */ bios_status = (bios_status >> 26) & 3;
if ((bios_status == 1) || (bios_status == 3)) *bytcr = true; else dev_info(dev, "BYT-CR not detected\n");
Here is the relevant part from the ACPI DSDT table:
Name (_ADR, Zero) // _ADR: Address Name (_HID, "80860F28" /* Intel SST Audio DSP */) // _HID: Hardware ID Name (_CID, "80860F28" /* Intel SST Audio DSP */) // _CID: Compatible ID Name (_DDN, "Intel(R) Low Power Audio Controller - 80860F28") // _DDN: DOS Device Name Name (_SUB, "80867270") // _SUB: Subsystem ID Name (_UID, One) // _UID: Unique ID
Name (RBUF, ResourceTemplate () { Memory32Fixed (ReadWrite, 0x12345678, // Address Base 0x00200000, // Address Length _Y08) Memory32Fixed (ReadWrite, 0xFE830000, // Address Base 0x00001000, // Address Length _Y09) Memory32Fixed (ReadWrite, 0x55AA55AA, // Address Base 0x00200000, // Address Length _Y0A) Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, ) { 0x0000001D, } })
Unlike many of the other DSDT dumps I've looked at, there is only one interrupt listed. Full ACPI DSDT table is at [1].
Since there is no IRQ at index 5, platform_get_irq will return -ENXIO. Couldn't we fall back to index 0 in this case? I would say that if the seemingly "correct" IRQ at index 5 does not even exist, we still have a better chance of picking the right one if we try the one at index 0. Or we could check the number of interrupts that are actually available.
The other option would be some kind of DMI-based quirk, but personally I would prefer to avoid that.. (In my opinion, there is way too much device specific code with the quirks etc already...)
Or do you have any other suggestions?
Thanks, Stephan
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