Hi Simon,
-----"Simon Glass" sjg@chromium.org schrieb: -----
Betreff: Re: [PATCH] acpi: device: Fix check for sequence number
Hi Wolfgang,
On Thu, 13 Aug 2020 at 01:23, Wolfgang Wallner wolfgang.wallner@br-automation.com wrote:
Hi Simon,
-----"Simon Glass" sjg@chromium.org schrieb: -----
Betreff: Re: [PATCH] acpi: device: Fix check for sequence number
Hi Wolfgang,
On Thu, 30 Jul 2020 at 06:47, Wolfgang Wallner wolfgang.wallner@br-automation.com wrote:
Currently the function acpi_check_seq() checks whether dev->req_seq is unequal to "-1", but it should actually check dev->seq. Change it to check dev->seq.
For req_seq the value "-1" would be a valid (meaning 'any'), while for seq the value "-1" means 'none' and is not valid.
Quoting the description of udevice in device.h:
- @req_seq: Requested sequence number for this device (-1 = any)
- @seq: Allocated sequence number for this device (-1 = none).
This is set up when the device is probed and will be uniquewithin the device's uclass.Signed-off-by: Wolfgang Wallner wolfgang.wallner@br-automation.com
Fixes: commit fefac0b0643b ("dm: acpi: Enhance acpi_get_name()")
lib/acpi/acpi_device.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
What problem are you seeing without this patch?
I see the following warning: "Device 'serial@18,2' has no seq".
In my case req_seq for the UART is -1 ("any"), while seq is 0. Why would we check for req_seq and not for seq in this function?
At present the ACPI device may not always be probed, and probing is when the sequence number is currently set up.
In my case the UART is already probed before the ACPI tables are generated.
I would expect req_seq to be set to the UART number, i.e. the value of the alias (uart0, uart1) that points to the node.
I wonder why that doesn't work in your case?
I did not have an alias for my serial. I have added one and now it works as expected.
I misunderstood how that code is expected to work. Thanks for the explanation, now it makes sense.
This also means that my patch is wrong and should be dropped. @Bin: please drop this patch.
Are you sure that all UARTs are probed before ACPI tables are created? Normally U-Boot would only probe the one being used for the console.
I have been thinking about dropping req_seq and doing everything when the device is bound, but haven't dug into it in detail yet.
regards, Wolfgang