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: <4dd25dca-f217-4abd-88e8-0a6b03760dd7@tuxedocomputers.com>
Date: Fri, 25 Oct 2024 17:40:26 +0200
From: Georg Gottleuber <ggo@...edocomputers.com>
To: Ulf Hansson <ulf.hansson@...aro.org>, Ben Chuang <benchuanggli@...il.com>
Cc: 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, Georg Gottleuber <ggo@...edocomputers.com>,
 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

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.

Kind regards,
Georg