On 28.06.2016 18:12, Duc Dang wrote:
On Tue, Jun 28, 2016 at 6:04 AM, Christopher Covington cov@codeaurora.org wrote:
Hi Tomasz,
On 06/28/2016 03:54 AM, Tomasz Nowicki wrote:
diff --git a/drivers/pci/host/mcfg-quirks.c b/drivers/pci/host/mcfg-quirks.c new file mode 100644 index 0000000..fb2b184 --- /dev/null +++ b/drivers/pci/host/mcfg-quirks.c @@ -0,0 +1,88 @@
+static bool pci_mcfg_fixup_match(struct pci_cfg_fixup *f,
struct acpi_table_header *mcfg_header)
+{
int olen = min_t(u8, strlen(f->oem_id), ACPI_OEM_ID_SIZE);
int tlen = min_t(u8, strlen(f->oem_table_id), ACPI_OEM_TABLE_ID_SIZE);
return (!strncmp(f->oem_id, mcfg_header->oem_id, olen) &&
!strncmp(f->oem_table_id, mcfg_header->oem_table_id, tlen) &&
f->oem_revision == mcfg_header->oem_revision);
+}
Ard's comments on v3 included:
"... exact OEM table/rev id matches ..." "... substring match ... out of the question ..."
I originally advocated the substring match approach because space-padding the input strings was unfamiliar. But given that some vendors have a "PLAT " then "PLAT2 " naming scheme, where the former needs quirks and the latter (hopefully) doesn't, I agree with Ard and think space-padded inputs is the better way to go. Sorry for the lack of foresight.
I think having OEM Table ID as "PLAT " and then "PLAT2 " (the the next version of the SoC) is common. So yes, matching full string is better as we can use "PLAT2 " in MCFG table and not worry about the "PLAT" sub-string match causes the quirk to be applied unintentionally.
Sorry, I forgot to address Ard's comment.
Note that platforms already shipped where OEM string has no padding will have change the firmware or add 0 padding to our quirk array IDs. So how about:
static bool pci_mcfg_fixup_match(struct pci_cfg_fixup *f, struct acpi_table_header *mcfg_header) { int olen = strnlen(mcfg_header->oem_id, ACPI_OEM_ID_SIZE); int tlen = strnlen(mcfg_header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
if (olen != strlen(f->oem_id) || tlen != strlen(f->oem_table_id)) return false;
return (!strncmp(f->oem_id, mcfg_header->oem_id, olen) && !strncmp(f->oem_table_id, mcfg_header->oem_table_id, tlen) && f->oem_revision == mcfg_header->oem_revision); }
This should work for all cases: 1. "PLAT" 2. "PLAT " padding 3. No need to change existing firmware
Tomasz