Peter Stuge (peter@stuge.se) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/590
-gerrit
commit a8dd8d5549e0c97dacc6ccb0c5d99f3eb9b32a42 Author: Peter Stuge peter@stuge.se Date: Fri Jan 27 22:17:09 2012 +0100
northbridge/intel/i945: CHECK_SLFRCS_ON_RESUME Kconfig option
Originally brought up by Sven Schnelle in March 2011 http://patchwork.coreboot.org/patch/2801/ http://www.coreboot.org/pipermail/coreboot/2011-March/064277.html
On some mainboards it may be neccessary to reset early during resume from S3 if the SLFRCS register indicates that a memory channel is not guaranteed to be in self-refresh.
On other mainboards, such as Lenovo X60 and T60, the check always creates false positives, effectively making it impossible to resume.
The SLFRCS register is documented on page 197 of
Mobile Intel® 945 Express Chipset Family Datasheet Document Number: 309219-006
which is publically available, and the register indicates if a memory channel is guaranteed to be in self-refresh mode if a bit is set (= 1), or that a memory channel *may or may not be* in self-refresh mode if a bit is clear (= 0).
The register can thus only be used to learn that RAM is positively in self-refresh. The register is reset by the PWROK signal, which *should* go low during S3 and go high again when resuming, so it is unsurprising that bits have already been reset by the time coreboot reads them.
Sven's measurements of the CKE signal on a ThinkPad shows that memory remains in self-refresh indefinitely, until coreboot re-initializes the memory controller, even when the SLFRCS bits were clear (= 0).
Boards which require a warm reset when SLFRCS bits are cleared must now explicitly enable the check in the mainboard Kconfig file.
All existing i945 mainboards except ThinkPads select the option, to ensure that this commit creates no regressions while solving the very real problem of ThinkPad mainboards being unable to resume from S3.
Change-Id: I02320675efb8fde05c371ef243ba5093a4da6d11 Signed-off-by: Peter Stuge peter@stuge.se --- src/mainboard/getac/p470/Kconfig | 1 + src/mainboard/ibase/mb899/Kconfig | 1 + src/mainboard/intel/d945gclf/Kconfig | 1 + src/mainboard/kontron/986lcd-m/Kconfig | 1 + src/mainboard/roda/rk886ex/Kconfig | 1 + src/northbridge/intel/i945/Kconfig | 9 +++++++++ src/northbridge/intel/i945/raminit.c | 4 ++-- 7 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/src/mainboard/getac/p470/Kconfig b/src/mainboard/getac/p470/Kconfig index ec30859..6ca11e5 100644 --- a/src/mainboard/getac/p470/Kconfig +++ b/src/mainboard/getac/p470/Kconfig @@ -23,6 +23,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy select ARCH_X86 select CPU_INTEL_SOCKET_MFCPGA478 select NORTHBRIDGE_INTEL_I945GM + select CHECK_SLFRCS_ON_RESUME select SOUTHBRIDGE_INTEL_I82801GX select SOUTHBRIDGE_TI_PCIXX12 select SUPERIO_SMSC_FDC37N972 diff --git a/src/mainboard/ibase/mb899/Kconfig b/src/mainboard/ibase/mb899/Kconfig index 02ccfab..ac87466 100644 --- a/src/mainboard/ibase/mb899/Kconfig +++ b/src/mainboard/ibase/mb899/Kconfig @@ -5,6 +5,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy select ARCH_X86 select CPU_INTEL_SOCKET_MFCPGA478 select NORTHBRIDGE_INTEL_I945GM + select CHECK_SLFRCS_ON_RESUME select SOUTHBRIDGE_INTEL_I82801GX select SUPERIO_WINBOND_W83627EHG select BOARD_HAS_FADT diff --git a/src/mainboard/intel/d945gclf/Kconfig b/src/mainboard/intel/d945gclf/Kconfig index 2b0161c..efc8025 100644 --- a/src/mainboard/intel/d945gclf/Kconfig +++ b/src/mainboard/intel/d945gclf/Kconfig @@ -23,6 +23,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy select ARCH_X86 select CPU_INTEL_SOCKET_441 select NORTHBRIDGE_INTEL_I945GC + select CHECK_SLFRCS_ON_RESUME select SOUTHBRIDGE_INTEL_I82801GX select SUPERIO_SMSC_LPC47M15X select BOARD_HAS_FADT diff --git a/src/mainboard/kontron/986lcd-m/Kconfig b/src/mainboard/kontron/986lcd-m/Kconfig index 01e4b2f..ec5c073 100644 --- a/src/mainboard/kontron/986lcd-m/Kconfig +++ b/src/mainboard/kontron/986lcd-m/Kconfig @@ -5,6 +5,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy select ARCH_X86 select CPU_INTEL_SOCKET_MFCPGA478 select NORTHBRIDGE_INTEL_I945GM + select CHECK_SLFRCS_ON_RESUME select SOUTHBRIDGE_INTEL_I82801GX select SUPERIO_WINBOND_W83627THG select BOARD_HAS_FADT diff --git a/src/mainboard/roda/rk886ex/Kconfig b/src/mainboard/roda/rk886ex/Kconfig index 7dfcc7d..d5de7dc 100644 --- a/src/mainboard/roda/rk886ex/Kconfig +++ b/src/mainboard/roda/rk886ex/Kconfig @@ -5,6 +5,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy select ARCH_X86 select CPU_INTEL_SOCKET_MFCPGA478 select NORTHBRIDGE_INTEL_I945GM + select CHECK_SLFRCS_ON_RESUME select SOUTHBRIDGE_INTEL_I82801GX select SOUTHBRIDGE_TI_PCI7420 select SUPERIO_SMSC_LPC47N227 diff --git a/src/northbridge/intel/i945/Kconfig b/src/northbridge/intel/i945/Kconfig index 9ba47da..42cc7ce 100644 --- a/src/northbridge/intel/i945/Kconfig +++ b/src/northbridge/intel/i945/Kconfig @@ -53,4 +53,13 @@ config MAXIMUM_SUPPORTED_FREQUENCY the board supports, despite what the chipset should be capable of.
+config CHECK_SLFRCS_ON_RESUME + def_bool n + help + On some boards it may be neccessary to hard reset early + during resume from S3 if the SLFRCS register indicates that + a memory channel is not guaranteed to be in self-refresh. + On other boards the check always creates a false positive, + effectively making it impossible to resume. + endif diff --git a/src/northbridge/intel/i945/raminit.c b/src/northbridge/intel/i945/raminit.c index a7fbaa4..d92c006 100644 --- a/src/northbridge/intel/i945/raminit.c +++ b/src/northbridge/intel/i945/raminit.c @@ -294,8 +294,8 @@ static void sdram_detect_errors(struct sys_info *sysinfo) reg8 |= (1<<7); pci_write_config8(PCI_DEV(0, 0x1f, 0), 0xa2, reg8);
- /* clear self refresh if not wake-up from suspend */ - if (sysinfo->boot_path != 2) { + /* clear self refresh status if check is disabled or not a resume */ + if (!CONFIG_CHECK_SLFRCS_ON_RESUME || sysinfo->boot_path != 2) { MCHBAR8(0xf14) |= 3; } else { /* Validate self refresh config */