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Date:   Tue, 9 May 2023 08:49:24 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Corentin Labbe <clabbe.montjoie@gmail.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
        pjones@redhat.com, deller@gmx.de, linux-fbdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: Cannot boot an i386-UEFI thinkpad lenovo tablet-2
Message-ID: <20230509064924.GB2065796@hirez.programming.kicks-ass.net>
References: <ZFnoXiZGGhuWDl2S@Red>
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On Tue, May 09, 2023 at 08:29:50AM +0200, Corentin Labbe wrote:

> The bios speak about a debug port, but I found nothing which seems a
> physical debug port output.  I tried to wire the microusb power port
> on a USB host, but the host fail to enumerate any device (I tried also
> a spetial USB cable with data/power separated to be sure the problem
> was not the host failling to give enough power)
> 
> The tablet has only one port, so I use a hub for keyboard and USB key.

USB debug port is probably that one port, USB debug also does not work
through a hub :/

USB debug in general is a giant pain in the rear and I've never had much
luck with is. If it's that old to still need a i386 kernel then it's
probably USB2 at best and that requires a special magical cable too :-(