Al Stone 8f8027c5f9 mailbox: PCC: erroneous error message when parsing ACPI PCCT ... There have been multiple reports of the following error message: [ 0.068293] Error parsing PCC subspaces from PCCT This error message is not correct. In multiple cases examined, the PCCT (Platform Communications Channel Table) concerned is actually properly constructed; the problem is that acpi_pcc_probe() which reads the PCCT is making the assumption that the only valid PCCT is one that contains subtables of one of two types: ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE or ACPI_PCCT_TYPE_HW_REDUCED_TYPE2. The number of subtables of these types are counted and as long as there is at least one of the desired types, the acpi_pcc_probe() succeeds. When no subtables of these types are found, regardless of whether or not any other subtable types are present, the error mentioned above is reported. In the cases reported to me personally, the PCCT contains exactly one subtable of type ACPI_PCCT_TYPE_GENERIC_SUBSPACE. The function acpi_pcc_probe() does not count it as a valid subtable, so believes there to be no valid subtables, and hence outputs the error message. An example of the PCCT being reported as erroneous yet perfectly fine is the following: Signature : "PCCT" Table Length : 0000006E Revision : 05 Checksum : A9 Oem ID : "XXXXXX" Oem Table ID : "XXXXX " Oem Revision : 00002280 Asl Compiler ID : "XXXX" Asl Compiler Revision : 00000002 Flags (decoded below) : 00000001 Platform : 1 Reserved : 0000000000000000 Subtable Type : 00 [Generic Communications Subspace] Length : 3E Reserved : 000000000000 Base Address : 00000000DCE43018 Address Length : 0000000000001000 Doorbell Register : [Generic Address Structure] Space ID : 01 [SystemIO] Bit Width : 08 Bit Offset : 00 Encoded Access Width : 01 [Byte Access:8] Address : 0000000000001842 Preserve Mask : 00000000000000FD Write Mask : 0000000000000002 Command Latency : 00001388 Maximum Access Rate : 00000000 Minimum Turnaround Time : 0000 To fix this, we count up all of the possible subtable types for the PCCT, and only report an error when there are none (which could mean either no subtables, or no valid subtables), or there are too many. We also change the logic so that if there is a valid subtable, we do try to initialize it per the PCCT subtable contents. This is a change in functionality; previously, the probe would have returned right after the error message and would not have tried to use any other subtable definition. Tested on my personal laptop which showed the error previously; the error message no longer appears and the laptop appears to operate normally. Signed-off-by: Al Stone <ahs3@redhat.com> Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>		2018-05-18 12:08:15 +02:00
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arm_mhu.c
bcm2835-mailbox.c
bcm-flexrm-mailbox.c	maillbox: bcm-flexrm-mailbox: Use dma_pool_zalloc()	2018-03-15 21:23:36 +05:30
bcm-pdc-mailbox.c
hi3660-mailbox.c	mailbox: Add support for Hi3660 mailbox	2018-03-20 11:15:54 +08:00
hi6220-mailbox.c
Kconfig	mailbox: Add support for Hi3660 mailbox	2018-03-20 11:15:54 +08:00
mailbox-altera.c
mailbox-sti.c
mailbox-test.c	vfs: do bulk POLL* -> EPOLL* replacement	2018-02-11 14:34:03 -08:00
mailbox-xgene-slimpro.c
mailbox.c	mailbox: reset txdone_method TXDONE_BY_POLL if client knows_txdone	2017-11-14 20:21:28 +05:30
mailbox.h
Makefile	mailbox: Add support for Hi3660 mailbox	2018-03-20 11:15:54 +08:00
omap-mailbox.c	mailbox/omap: unregister mbox class	2017-11-14 20:21:35 +05:30
pcc.c	mailbox: PCC: erroneous error message when parsing ACPI PCCT	2018-05-18 12:08:15 +02:00
pl320-ipc.c
platform_mhu.c
qcom-apcs-ipc-mailbox.c	mailbox: qcom: Create APCS child device for clock controller	2018-02-04 12:16:23 +05:30
rockchip-mailbox.c
tegra-hsp.c
ti-msgmgr.c	mailbox: ti-msgmgr: Use %zu for size_t print format	2018-01-10 10:15:32 +05:30