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

[Niklas Cassel]

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@xxxxxxxxxxx>
> 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@xxxxxxxxxxxxxxx
>     Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
>     Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> 
> 
> 
> 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.


Kind regards,
Niklas