linux-kernel - Re: [PATCH 1/2] mmc: sdhci-pci-gli: GL9767: Fix low power mode on the set clock function

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Message-ID: <CACT4zj-YT21rFFg=VYk1OF-HEefVYR=d=JXYbUz-kGrj_RD85g@mail.gmail.com>
Date: Tue, 29 Oct 2024 10:14:25 +0800
From: Ben Chuang <benchuanggli@...il.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
Cc: Georg Gottleuber <ggo@...edocomputers.com>, adrian.hunter@...el.com, 
	victor.shih@...esyslogic.com.tw, greg.tu@...esyslogic.com.tw, 
	ben.chuang@...esyslogic.com.tw, HL.Liu@...esyslogic.com.tw, 
	Lucas.Lai@...esyslogic.com.tw, victorshihgli@...il.com, 
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Werner Sembach <wse@...edocomputers.com>, cs@...edo.de
Subject: Re: [PATCH 1/2] mmc: sdhci-pci-gli: GL9767: Fix low power mode on the
 set clock function

On Mon, Oct 28, 2024 at 7:44 PM Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
> On Fri, 25 Oct 2024 at 17:40, Georg Gottleuber <ggo@...edocomputers.com> wrote:
> >
> > Hello Ben, hello Uffe,
> >
> > thank you for this fix.
> >
> > Am 25.10.24 um 15:22 schrieb Ulf Hansson:
> > > + Georg
> > >
> > > On Fri, 25 Oct 2024 at 08:01, Ben Chuang <benchuanggli@...il.com> wrote:
> > >>
> > >> From: Ben Chuang <ben.chuang@...esyslogic.com.tw>
> > >>
> > >> On sdhci_gl9767_set_clock(), the vendor header space(VHS) is read-only
> > >> after calling gl9767_disable_ssc_pll() and gl9767_set_ssc_pll_205mhz().
> > >> So the low power negotiation mode cannot be enabled again.
> > >> Introduce gl9767_set_low_power_negotiation() function to fix it.
> > >>
> > >> The explanation process is as below.
> > >>
> > >> static void sdhci_gl9767_set_clock()
> > >> {
> > >>         ...
> > >>         gl9767_vhs_write();
> > >>         ...
> > >>         value |= PCIE_GLI_9767_CFG_LOW_PWR_OFF;
> > >>         pci_write_config_dword(pdev, PCIE_GLI_9767_CFG, value); <--- (a)
> > >>
> > >>         gl9767_disable_ssc_pll(); <--- (b)
> > >>         sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > >>
> > >>         if (clock == 0)
> > >>                 return;  <-- (I)
> > >>
> > >>         ...
> > >>         if (clock == 200000000 && ios->timing == MMC_TIMING_UHS_SDR104) {
> > >>                 ...
> > >>                 gl9767_set_ssc_pll_205mhz(); <--- (c)
> > >>         }
> > >>         ...
> > >>         value &= ~PCIE_GLI_9767_CFG_LOW_PWR_OFF;
> > >>         pci_write_config_dword(pdev, PCIE_GLI_9767_CFG, value); <-- (II)
> > >>         gl9767_vhs_read();
> > >> }
> > >>
> > >> (a) disable low power negotiation mode. When return on (I), the low power
> > >> mode is disabled.  After (b) and (c), VHS is read-only, the low power mode
> > >> cannot be enabled on (II).
> > >>
> > >> Fixes: d2754355512e ("mmc: sdhci-pci-gli: Set SDR104's clock to 205MHz and enable SSC for GL9767")
> > >
> > > Is this the same problem as being reported in
> > > https://lore.kernel.org/all/41c1c88a-b2c9-4c05-863a-467785027f49@tuxedocomputers.com/
> > >
> > > ?
> >
> > Yes, this patch fixes
> > https://bugzilla.kernel.org/show_bug.cgi?id=219284
> >
> > This makes my patch obsolete.
>
> Thanks to both of you for helping out and fixing the problem!
>
> I added Georg's reported/tested-by tag when applying and queued this
> up as a fix with a stable tag.
>
> Kind regards
> Uffe

Hi Georg and Uffe,

The original test reported on bugzilla that only Intel laptops had issues.
AMD laptops without this patch seem to have no impact.

I'm not sure if this patch is related to the originally reported issue.
Thanks for the help.

Best regards,
Ben Chuang