Re: [PATCH V3] ahci: Marvell 88SE9215 controllers prefer DMA for ATAPI

[Huacai Chen <chenhuacai@kernel.org>]

On Tue, Mar 18, 2025 at 4:02 PM Niklas Cassel <cassel@kernel.org> wrote:
>
> Hello Huacai,
>
> On Wed, Mar 12, 2025 at 04:47:55PM +0100, Niklas Cassel wrote:
> > On Wed, Mar 12, 2025 at 09:46:54PM +0800, Huacai Chen wrote:
> > > We use CD/DVD drives under Marvell 88SE9215 SATA controller on many
> > > Loongson-based machines. We found its PIO doesn't work well, and on the
> > > opposite its DMA seems work very well. We don't know the detail of the
> > > 88SE9215 SATA controller, but we have tested different CD/DVD drives
> > > and they all have problems under 88SE9215 (but they all work well under
> > > an Intel SATA controller). So we can define a new dedicated AHCI board
> > > id named board_ahci_yes_fbs_atapi_dma for 88SE9215, and for this id we
> > > set the AHCI_HFLAG_ATAPI_DMA_QUIRK and ATA_QUIRK_ATAPI_MOD16_DMA flags
> > > on the SATA controller to prefer ATAPI DMA.
> >
> > This is a wall of text.
> >
> > Could you please use paragraphs? (with an empty line between paragraphs).
> >
> > (There can be multiple sentences in one paragraph.)
> >
> > This is a good example:
> >
> > commit 6bdbb73dc8d99fbb77f5db79dbb6f108708090b4
> > Author: Bibo Mao <maobibo@loongson.cn>
> > Date:   Sat Mar 8 13:52:04 2025 +0800
> >
> >     LoongArch: KVM: Fix GPA size issue about VM
> >
> >     Physical address space is 48 bit on Loongson-3A5000 physical machine,
> >     however it is 47 bit for VM on Loongson-3A5000 system. Size of physical
> >     address space of VM is the same with the size of virtual user space (a
> >     half) of physical machine.
> >
> >     Variable cpu_vabits represents user address space, kernel address space
> >     is not included (user space and kernel space are both a half of total).
> >     Here cpu_vabits, rather than cpu_vabits - 1, is to represent the size of
> >     guest physical address space.
> >
> >     Also there is strict checking about page fault GPA address, inject error
> >     if it is larger than maximum GPA address of VM.
> >
> >     Cc: stable@vger.kernel.org
> >     Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> >     Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> >
> >
> >
> > Otherwise, this looks good to me.
>
>
> If you want this patch to be queued up for 6.15, please send a new version
> this week, because after this week, it will instead be queued up for 6.16.
OK, I will send V4 today, sorry for the delay.

Huacai
>
>
> Kind regards,
> Niklas