Added a patch from upstream to fix this error, which as it turns out
is an erroneous message -- i.e., there is actually no error. Please
see the patch file itself for further details.
Signed-off-by: Al Stone <ahs3@xxxxxxxxxx>
---
...-erroneous-error-message-when-parsing-ACP.patch | 241 +++++++++++++++++++++
kernel.spec | 4 +
2 files changed, 245 insertions(+)
create mode 100644 0001-mailbox-PCC-erroneous-error-message-when-parsing-ACP.patch
diff --git a/0001-mailbox-PCC-erroneous-error-message-when-parsing-ACP.patch b/0001-mailbox-PCC-erroneous-error-message-when-parsing-ACP.patch
new file mode 100644
index 00000000..110ad0f5
--- /dev/null
+++ b/0001-mailbox-PCC-erroneous-error-message-when-parsing-ACP.patch
@@ -0,0 +1,241 @@
+From 8f8027c5f935bf02bdc8806c109ddbb0e402283c Mon Sep 17 00:00:00 2001
+From: Al Stone <ahs3@xxxxxxxxxx>
+Date: Wed, 16 May 2018 16:01:41 -0600
+Subject: [PATCH] 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@xxxxxxxxxx>
+Reviewed-by: Prashanth Prakash <pprakash@xxxxxxxxxxxxxx>
+Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
+---
+ drivers/mailbox/pcc.c | 81 ++++++++++++++++++++++++---------------------------
+ 1 file changed, 38 insertions(+), 43 deletions(-)
+
+diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
+index 3ef7f036ceea..fc3c237daef2 100644
+--- a/drivers/mailbox/pcc.c
++++ b/drivers/mailbox/pcc.c
+@@ -373,33 +373,24 @@ static const struct mbox_chan_ops pcc_chan_ops = {
+ };
+
+ /**
+- * parse_pcc_subspace - Parse the PCC table and verify PCC subspace
+- * entries. There should be one entry per PCC client.
++ * parse_pcc_subspaces -- Count PCC subspaces defined
+ * @header: Pointer to the ACPI subtable header under the PCCT.
+ * @end: End of subtable entry.
+ *
+- * Return: 0 for Success, else errno.
++ * Return: If we find a PCC subspace entry of a valid type, return 0.
++ * Otherwise, return -EINVAL.
+ *
+ * This gets called for each entry in the PCC table.
+ */
+ static int parse_pcc_subspace(struct acpi_subtable_header *header,
+ const unsigned long end)
+ {
+- struct acpi_pcct_hw_reduced *pcct_ss;
+-
+- if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) {
+- pcct_ss = (struct acpi_pcct_hw_reduced *) header;
++ struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;
+
+- if ((pcct_ss->header.type !=
+- ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE)
+- && (pcct_ss->header.type !=
+- ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2)) {
+- pr_err("Incorrect PCC Subspace type detected\n");
+- return -EINVAL;
+- }
+- }
++ if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)
++ return 0;
+
+- return 0;
++ return -EINVAL;
+ }
+
+ /**
+@@ -449,8 +440,8 @@ static int __init acpi_pcc_probe(void)
+ struct acpi_table_header *pcct_tbl;
+ struct acpi_subtable_header *pcct_entry;
+ struct acpi_table_pcct *acpi_pcct_tbl;
++ struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
+ int count, i, rc;
+- int sum = 0;
+ acpi_status status = AE_OK;
+
+ /* Search for PCCT */
+@@ -459,43 +450,41 @@ static int __init acpi_pcc_probe(void)
+ if (ACPI_FAILURE(status) || !pcct_tbl)
+ return -ENODEV;
+
+- count = acpi_table_parse_entries(ACPI_SIG_PCCT,
+- sizeof(struct acpi_table_pcct),
+- ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE,
+- parse_pcc_subspace, MAX_PCC_SUBSPACES);
+- sum += (count > 0) ? count : 0;
+-
+- count = acpi_table_parse_entries(ACPI_SIG_PCCT,
+- sizeof(struct acpi_table_pcct),
+- ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2,
+- parse_pcc_subspace, MAX_PCC_SUBSPACES);
+- sum += (count > 0) ? count : 0;
++ /* Set up the subtable handlers */
++ for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;
++ i < ACPI_PCCT_TYPE_RESERVED; i++) {
++ proc[i].id = i;
++ proc[i].count = 0;
++ proc[i].handler = parse_pcc_subspace;
++ }
+
+- if (sum == 0 || sum >= MAX_PCC_SUBSPACES) {
+- pr_err("Error parsing PCC subspaces from PCCT\n");
++ count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
++ sizeof(struct acpi_table_pcct), proc,
++ ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
++ if (count == 0 || count > MAX_PCC_SUBSPACES) {
++ pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
+ return -EINVAL;
+ }
+
+- pcc_mbox_channels = kzalloc(sizeof(struct mbox_chan) *
+- sum, GFP_KERNEL);
++ pcc_mbox_channels = kzalloc(sizeof(struct mbox_chan) * count, GFP_KERNEL);
+ if (!pcc_mbox_channels) {
+ pr_err("Could not allocate space for PCC mbox channels\n");
+ return -ENOMEM;
+ }
+
+- pcc_doorbell_vaddr = kcalloc(sum, sizeof(void *), GFP_KERNEL);
++ pcc_doorbell_vaddr = kcalloc(count, sizeof(void *), GFP_KERNEL);
+ if (!pcc_doorbell_vaddr) {
+ rc = -ENOMEM;
+ goto err_free_mbox;
+ }
+
+- pcc_doorbell_ack_vaddr = kcalloc(sum, sizeof(void *), GFP_KERNEL);
++ pcc_doorbell_ack_vaddr = kcalloc(count, sizeof(void *), GFP_KERNEL);
+ if (!pcc_doorbell_ack_vaddr) {
+ rc = -ENOMEM;
+ goto err_free_db_vaddr;
+ }
+
+- pcc_doorbell_irq = kcalloc(sum, sizeof(int), GFP_KERNEL);
++ pcc_doorbell_irq = kcalloc(count, sizeof(int), GFP_KERNEL);
+ if (!pcc_doorbell_irq) {
+ rc = -ENOMEM;
+ goto err_free_db_ack_vaddr;
+@@ -509,18 +498,24 @@ static int __init acpi_pcc_probe(void)
+ if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
+ pcc_mbox_ctrl.txdone_irq = true;
+
+- for (i = 0; i < sum; i++) {
++ for (i = 0; i < count; i++) {
+ struct acpi_generic_address *db_reg;
+- struct acpi_pcct_hw_reduced *pcct_ss;
++ struct acpi_pcct_subspace *pcct_ss;
+ pcc_mbox_channels[i].con_priv = pcct_entry;
+
+- pcct_ss = (struct acpi_pcct_hw_reduced *) pcct_entry;
++ if (pcct_entry->type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
++ pcct_entry->type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
++ struct acpi_pcct_hw_reduced *pcct_hrss;
++
++ pcct_hrss = (struct acpi_pcct_hw_reduced *) pcct_entry;
+
+- if (pcc_mbox_ctrl.txdone_irq) {
+- rc = pcc_parse_subspace_irq(i, pcct_ss);
+- if (rc < 0)
+- goto err;
++ if (pcc_mbox_ctrl.txdone_irq) {
++ rc = pcc_parse_subspace_irq(i, pcct_hrss);
++ if (rc < 0)
++ goto err;
++ }
+ }
++ pcct_ss = (struct acpi_pcct_subspace *) pcct_entry;
+
+ /* If doorbell is in system memory cache the virt address */
+ db_reg = &pcct_ss->doorbell_register;
+@@ -531,7 +526,7 @@ static int __init acpi_pcc_probe(void)
+ ((unsigned long) pcct_entry + pcct_entry->length);
+ }
+
+- pcc_mbox_ctrl.num_chans = sum;
++ pcc_mbox_ctrl.num_chans = count;
+
+ pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);
+
+--
+2.14.3
+
diff --git a/kernel.spec b/kernel.spec
index 943cded5..c2706996 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -618,6 +618,10 @@ Patch502: input-rmi4-remove-the-need-for-artifical-IRQ.patch
# rhbz 1509461
Patch503: v3-2-2-Input-synaptics---Lenovo-X1-Carbon-5-should-use-SMBUS-RMI.patch
+# rhbz 1435837
+# https://www.spinics.net/lists/linux-acpi/msg82405.html
+Patch504: 0001-mailbox-PCC-erroneous-error-message-when-parsing-ACP.patch
+
# END OF PATCH DEFINITIONS
%endif
--
2.14.3
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