On Tue, 17 Nov 2020 at 03:44, Y.b. Lu <yangbo.lu@xxxxxxx> wrote: > > Hi Uffe, > > > -----Original Message----- > > From: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > Sent: Monday, November 16, 2020 7:27 PM > > To: Y.b. Lu <yangbo.lu@xxxxxxx> > > Cc: linux-mmc@xxxxxxxxxxxxxxx; Adrian Hunter <adrian.hunter@xxxxxxxxx> > > Subject: Re: [PATCH] mmc: export sd3_bus_mode to user space > > > > On Mon, 2 Nov 2020 at 08:26, Yangbo Lu <yangbo.lu@xxxxxxx> wrote: > > > > > > There was no way for user to know what UHS-I modes the SD card > > > supporting. We might not know, even the highest speed mode > > > failed to use and fell back to a lower speed mode. > > > > > > This patch is to export sd3_bus_mode to user space to check. > > > > Well, even if the user would know, what can it do about it? > > For user, they can check the card speed modes capability, if they want to know. > For developer, they can know whether card is working on highest speed mode as expect. If not, they know there is issue needed checking. > > > > > Sound like you are looking for some debugging feature instead? > > Yes. I think we may need a way to know whether SD card is working on the highest speed mode as expect. > Otherwise, we are not able to realize issue if card just fall back to a lower speed mode to work. > Any suggestion on this? > > Thanks a lot. Well, perhaps we should look into extending the debugfs node for the card. See mmc_add_card_debugfs(). [...] Kind regards Uffe
