| Message ID | b3a31c5a-7090-ff15-c90d-dfeab221471f@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Thu, May 17, 2018 at 12:01 AM, Al Stone <ahs3@redhat.com> wrote: > 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. I'd like to know the Prashanth's opinion here. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 5/17/2018 4:24 AM, Rafael J. Wysocki wrote: > On Thu, May 17, 2018 at 12:01 AM, Al Stone <ahs3@redhat.com> wrote: >> 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. > I'd like to know the Prashanth's opinion here. Looks good. Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org> -- Thanks, Prashanth -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thursday, May 17, 2018 9:48:39 PM CEST Prakash, Prashanth wrote: > > On 5/17/2018 4:24 AM, Rafael J. Wysocki wrote: > > On Thu, May 17, 2018 at 12:01 AM, Al Stone <ahs3@redhat.com> wrote: > >> 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. > > I'd like to know the Prashanth's opinion here. > > Looks good. > > Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org> Applied, thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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);
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> Cc: Jassi Brar <jassisinghbrar@gmail.com> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> --- drivers/mailbox/pcc.c | 81 ++++++++++++++++++++----------------------- 1 file changed, 38 insertions(+), 43 deletions(-)