Web lists-archives.com

Re: [PATCH] mfd: Fix RTS5227 (and others) powermanagement


On 06-12-17 12:21, Hans de Goede wrote:
Commit 8275b77a1513 ("mfd: rts5249: Add support for RTS5250S power
saving") adds powersaving support for device-ids 5249 524a and 525a.

But as a side effect it breaks ASPM support for all the other device-ids,
causing e.g. the Haswell CPU on a Lenovo T440s to not go into a higher
c-state then PC3, while previously it would go to PC7, causing the
machine to idle at 7.4W instead of 6.6W!

The problem here is the new option.dev_aspm_mode field, which only gets
explicitly initialized in the new code for the device-ids 5249 524a and
525a. Leaving the dev_aspm_mode 0 for the other device-ids.

The default dev_aspm_mode 0 is mapped to DEV_ASPM_DISABLE, but the
old behavior of calling rtsx_pci_enable_aspm() when idle and
rtsx_pci_disable_aspm() when busy happens when dev_aspm_mode ==

This commit changes the enum so that 0 = DEV_ASPM_DYNAMIC matching the
old default behavior, fixing the pm regression with the other device-ids.

Cc: Rui Feng <rui_feng@xxxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>


2 remarks:

1. As this is a regression in 4.15, please queue this up as a fix for 4.15
   (I prioritized bisecting this, which took me a whole day to get a fix
    ready in time for 4.15).

2. This bit of the original commit also looks weird, but I don't have the
hardware in case, Rui Feng should probably take a look at this:

@@ -1063,6 +1185,16 @@ static int rtsx_pci_init_hw(struct rtsx_pcr *pcr)
 	if (err < 0)
 		return err;

+	switch (PCI_PID(pcr)) {
+	case PID_5250:
+	case PID_524A:
+	case PID_525A:
+		rtsx_pci_write_register(pcr, PM_CLK_FORCE_CTL, 1, 1);
+		break;
+	default:
+		break;
+	}
 	/* Enable clk_request_n to enable clock power management */
 	rtsx_pci_write_config_byte(pcr, pcr->pcie_cap + PCI_EXP_LNKCTL + 1, 1);
 	/* Enter L1 when host tx idle */

The PID5250 looks weird here, the rtsx_pci_ids table does not contain
it; and neither does the switch (PCI_PID(pcr)) in rtsx_pci_init_chip()
at the same time the commit does make changes to the codepaths for
the 5249... ?



  include/linux/mfd/rtsx_pci.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mfd/rtsx_pci.h b/include/linux/mfd/rtsx_pci.h
index a2a1318a3d0c..c3d3f04d8cc6 100644
--- a/include/linux/mfd/rtsx_pci.h
+++ b/include/linux/mfd/rtsx_pci.h
@@ -915,10 +915,10 @@ enum PDEV_STAT  {PDEV_STAT_IDLE, PDEV_STAT_RUN};
enum dev_aspm_mode {